FIX: doc imports
Bunch of doc build cleanups

closes #4418.

Jinja2 from pip doesn’t work for python 3 so it's a moot point. 
 i should say it doesn't work for py3.2
 also not sure how to deal with the relative import issue i'll try the abs import
 arg

http://stackoverflow.com/questions/16981921/python-3-relative-imports
 Maybe put an `__init__.py` in doc and then import with doc at top level.
 or just do sphinxext and then just `from sphinext.blahblah import`
 i got it to build....issue is that conf.py lists plot_directives from matplotlib but then pandas includes its own.... not sure what that's about
 now i'm fixing the slew of python3 incompatible doc examples
 wow almost all were fixed by this single line

``` python
from pandas.compat import lzip as zip
```
 could make it explicit with these two lines:

``` bash
perl -pi -e "s/zip/lzip/g" ./doc/**/*.py
perl -pi -e "s/from pandas.compat import lzip as zip/from pandas.compat import lzip/" ./doc/**/*.py
```

so it's explicit. added terminating slash
 arg these compat issues are SO annoying
 bottom line for now is that the docs need to be able to be built on py2.7 which they can't be right now
 @cpcloud just revert my edits to the docs (i.e., back before the merge commit from jreback), dump everything but the docs/*.py changes and commit it.  They worked before that, if we're only building on 2.7, then who cares about compatibility?
 I think it would be:

```
git checkout 338f3406fadc6d114accbc94fac6c7ba075a10f5 -- docs/**/*.py docs/*.py
```
 this fixes the doc building??
 not quite...still need to add the changes to examples for py3 compat
 ohhh :-/
 @cpcloud after you fix this, maybe we should add docs build to Travis on 2.7 so that changes to docs to stop them from building don't happen again.

Also, I apologize for not catching this - I just didn't think to run make docs. 
 no problem...happy that i can now run py3 except for docs!

add to slow build or "production"? i think production since that has `scikits.timeseries`
 also getting some use out of `vim` `grep` which i should probably use more often
 actually `Ack` as it turns out is _much_ better
 @cpcloud are you using the vim ack plugin? very useful.  That + Ctrl-P is really helpful.
 i love ctrl+p!
 like emacs ido-mode
 i feel like this is attack of the killer `range`s!
 i'll add the doc build to this PR
 ok whew got them working ... fixes on the way
 yeah so i don't think the doc build on travis is a good idea

would have to install R which requires a whole boatload of packages (55 MB d'load) which will be breathtakingly slow when travis is running in ~~1990~~ 28.8K mode
 @jreback ok 2 merge?
 all docs fixed??? crazy

ok
