TST/BUG: fix bs4 tests that were getting erroneously run when lxml is installed but not bs4
also maybe list the deps for lxml as well

e.g.
`sudo apt-get install libxml2 libxslt1.1 libxslt-dev`
 fyi....i get this on 32-bit machine.....(this is on master)
and I uninstalled xlml,bs4 then reinstalled

```

vagrant@precise32:~/pandas_master$ nosetests -A 'not slow' pandas/io/tests/test_html.py
........................F.............................................
======================================================================
FAIL: test_banklist_no_match (pandas.io.tests.test_html.TestBs4LxmlParser)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vagrant/pandas_master/pandas/io/tests/test_html.py", line 172, in test_banklist_no_match
    dfs = self.run_read_html(self.banklist_data, attrs={'id': 'table'})
  File "/home/vagrant/pandas_master/pandas/io/tests/test_html.py", line 393, in run_read_html
    return _run_read_html(parser, *args, **kwargs)
  File "/home/vagrant/pandas_master/pandas/io/tests/test_html.py", line 74, in _run_read_html
    infer_types, attrs)
  File "/home/vagrant/pandas_master/pandas/io/html.py", line 733, in _parse
    tables = p.parse_tables()
  File "/home/vagrant/pandas_master/pandas/io/html.py", line 160, in parse_tables
    tables = self._parse_tables(self._build_doc(), self.match, self.attrs)
  File "/home/vagrant/pandas_master/pandas/io/html.py", line 391, in _parse_tables
    raise AssertionError('No tables found')
AssertionError: No tables found

----------------------------------------------------------------------
Ran 70 tests in 10.158s

FAILED (failures=1)
vagrant@precise32:~/pandas_master$ python ci/print_versions.py 

INSTALLED VERSIONS
------------------
Python: 2.7.3.final.0
OS: Linux 3.2.0-23-generic-pae #36-Ubuntu SMP Tue Apr 10 22:19:09 UTC 2012 i686
LC_ALL: en_US
LANG: en_US

Cython: 0.15.1
Numpy: 1.7.0
Scipy: 0.11.0
statsmodels: 0.5.0.dev-1bbd4ca
    patsy: 0.1.0
scikits.timeseries: Not installed
dateutil: 2.1
pytz: 2011k
PyTables: 2.4.0
    numexpr: 2.0.1
matplotlib: Not installed
openpyxl: 1.6.1
xlrd: 0.9.2
xlwt: 0.7.5
sqlalchemy: Not installed
lxml: 3.2.1
bs4: 4.0.2
html5lib: 1.0b1
```
 can u post a link to your vagrant box so i can tinker
 you're _not_ using anaconda correct?
 oh gosh `print_versions.py` doesn't work for me, darn those line endings...
 not using anaconda!

how do I post a link to my box?
 i think `vagrant package --base my_base_box` and then share a link 2 it through Dropbox or some other means
 why the heck is only ONE test failing here?!?
 alright....what e-mail address?
 cpcloud@gmail.com
On Jun 3, 2013 2:17 PM, "jreback" notifications@github.com wrote:

> alright....what e-mail address?
> 
> —
> Reply to this email directly or view it on GitHubhttps://github.com/pydata/pandas/pull/3741#issuecomment-18860182
> .
 ok....sent you the link...prob about 1 more hour till upload is done ...big file 1.7gb!
 whew that's big. thanks. here's the output of my current precise32 setup

```
INSTALLED VERSIONS
------------------
Python: 2.7.3.final.0
OS: Linux 3.2.0-45-generic-pae #70-Ubuntu SMP Wed May 29 20:31:05 UTC 2013 i686
LC_ALL: en_US
LANG: en_US

Cython: 0.19.1
Numpy: 1.7.1
Scipy: 0.12.0
statsmodels: 0.5.0.dev-1bbd4ca
    patsy: Not installed
scikits.timeseries: Not installed
dateutil: 2.1
pytz: 2013b
PyTables: 3.0.0
    numexpr: 2.1
matplotlib: 1.2.1
openpyxl: 1.6.2
xlrd: 0.9.2
xlwt: 0.7.5
sqlalchemy: Not installed
lxml: 3.2.1
bs4: 4.2.1
html5lib: 1.0b1
```
 I have bs4 4.0.2
 tried with that and can repro
 @jreback drop into `pdb` and press `u` followed by

``` python
import bs4
soup  = bs4.BeautifulSoup(self._setup_build_doc())
soup
```

and you will see the root of the error is invalid markup.
 this pr fixes that failing test
 hmm....mine actually looks ok (it returns a big string), no error
 it had to with the integrity of `banklist.html`
 u don't get a bunch of extra whitespace?
 fyi...also not sure if you can grab a bs4/lxml error message and put that on your no tables message, e.g.

AssertionError("not tables: <invalid markup>") or something
 when i print soup just prints an html like string
 hm check out what i get:

``````
   /   s   c   r   i   p   t   &gt;
   n   o   s   c   r   i   p   t   &gt;
   a       h   r   e   f   =   "   h   t   t   p   :   /   /   w   w   w   .   o   m   n   i   t   u   r   e   .   c   o   m   "       t   i   t   l   e   =   "   W   e   b       A   n   a   l   y   t   i   c   s   "   &gt;
   i   m   g       s   r   c   =   "   h   t   t   p   :   /   /   f   d   i   c   .   1   2   2   .   2   o   7   .   n   e   t   /   b   /   s   s   /   f   d   i   c   g   o   v   p   r   o   d   /   1   /   H   .   2   1   -   -   N   S   /   0   ?   [   A   Q   B   ]   %   2   6   c   l   =   S   e   s   s   i   o   n   %   2   6   A   Q   E   "       h   e   i   g   h   t   =   "   1   "       w   i   d   t   h   =   "   1   "       b   o   r   d   e   r   =   "   0   "       a   l   t   =   "   "       /   &gt;   /       &gt;
   /   n   o   s   c   r   i   p   t   &gt;

   !   -   -   /   D   O       N   O   T       R   E   M   O   V   E   /   -   -   &gt;
   !   -   -       E   n   d       S   i   t   e   C   a   t   a   l   y   s   t       c   o   d   e           e   r   s   i   o   n   :       H   .   2   1   .       -   -   &gt;
   !   -   -       e   n   d       f   o   o   t   e   r       -   -   &gt;
   !   -   -       E   N   D       F   O   O   T   E   R       I   N   C   L   U   D   E       -   -   &gt```
``````
 with

```

INSTALLED VERSIONS
------------------
Python: 2.7.3.final.0
OS: Linux 3.2.0-45-generic-pae #70-Ubuntu SMP Wed May 29 20:31:05 UTC 2013 i686
LC_ALL: en_US
LANG: en_US

Cython: 0.19.1
Numpy: 1.7.1
Scipy: 0.12.0
statsmodels: 0.5.0.dev-1bbd4ca
    patsy: Not installed
scikits.timeseries: Not installed
dateutil: 2.1
pytz: 2013b
PyTables: 3.0.0
    numexpr: 2.1
matplotlib: 1.2.1
openpyxl: 1.6.2
xlrd: 0.9.2
xlwt: 0.7.5
sqlalchemy: Not installed
lxml: 3.2.1
bs4: 4.0.2
html5lib: 1.0b1
```
 dl'ing ur vagrant box now...2 MB ish / sec shouldn't be too long
 hmmm...i get what looks like valid output.....
 dude it's so cool that u can send me a whole computer over the interwebz
 i get the same extra whitespace with ur vagrant box
 ```
   i   p   t   &gt;
   s   c   r   i   p   t       l   a   n   g   u   a   g   e   =   "   J   a   v   a   S   c   r   i   p   t   "       t   y   p   e   =   "   t   e   x   t   /   j   a   v   a   s   c   r   i   p   t   "   &gt; 
   i   f   (   n   a   v   i   g   a   t   o   r   .   a   p   p   V   e   r   s   i   o   n   .   i   n   d   e   x   O   f   (   '   M   S   I   E   '   )   &gt;   =   0   )   d   o   c   u   m   e   n   t   .   w   r   i   t   e   (   u   n   e   s   c   a   p   e   (   '   %   3   C   '   )   +   '   \   !   -       +   '   -   '   )
   /   s   c   r   i   p   t   &gt;
   n   o   s   c   r   i   p   t   &gt;
   a       h   r   e   f   =   "   h   t   t   p   :   /   /   w   w   w   .   o   m   n   i   t   u   r   e   .   c   o   m   "       t   i   t   l   e   =   "   W   e   b       A   n   a   l   y   t   i   c   s   "   &gt;
   i   m   g       s   r   c   =   "   h   t   t   p   :   /   /   f   d   i   c   .   1   2   2   .   2   o   7   .   n   e   t   /   b   /   s   s   /   f   d   i   c   g   o   v   p   r   o   d   /   1   /   H   .   2   1   -   -   N   S   /   0   ?   [   A   Q   B   ]   %   2   6   c   l   =   S   e   s   s   i   o   n   %   2   6   A   Q   E   "       h   e   i   g   h   t   =   "   1   "       w   i   d   t   h   =   "   1   "       b   o   r   d   e   r   =   "   0   "       a   l   t   =   "   "       /   &gt;   /       &gt;
   /   n   o   s   c   r   i   p   t   &gt;

   !   -   -   /   D   O       N   O   T       R   E   M   O   V   E   /   -   -   &gt;
   !   -   -       E   n   d       S   i   t   e   C   a   t   a   l   y   s   t       c   o   d   e           e   r   s   i   o   n   :       H   .   2   1   .       -   -   &gt;
   !   -   -       e   n   d       f   o   o   t   e   r       -   -   &gt;
   !   -   -       E   N   D       F   O   O   T   E   R       I   N   C   L   U   D   E       -   -   &gt
```
 oh....ok....then that is fine (that's what your fix did)

weird that it doesn't raise?
 i literally did nothing except download it followed by `v init jreback-precise32 package.box && v up && v ssh` (I've aliased `v` to `vagrant`)
