CLN/TST remove compat.scipy
re-branch of https://github.com/pydata/pandas/pull/7253#issue-34432164

-Move `percentileofscore` to `stats.misc`; Update `percentileRank` to reflect the move.
-Change testing references to `compat.scipy.rankdata()` , to use `scipy.stats.rankdata` directly
-Delete compat.scipy 

Does this mean you can no longer use `.rank` without scipy? (The whole point of that compat file was so that scipy wasn't a dependancy, right?)
 Ah ok, this is just in tests. Cool.
 yeh I think was just to check vs scipy (and maybe it wasn't included in testing suite at that point)
 @hayd, `_skip_if_no_scipy` should probably be in there. I'll push up the change. 
 Sorry guys... I'm having some git-problems...
 It looks like you should remove the last commit (the merge one): http://stackoverflow.com/a/6866485/1240268

(I would first check that's the case with `git log` before you nuke it...)

Then force push back to this PR: `git push origin CompatScipy -f`.

I think you forgot to `import nose`, see the [allowed failure](https://travis-ci.org/pydata/pandas/jobs/26478521).

```
ERROR: pandas.tests.test_tseries.test_rank
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/travis/virtualenv/python2.7.6/lib/python2.7/site-packages/nose-1.3.3-py2.7.egg/nose/case.py", line 197, in runTest
    self.test(*self.arg)
  File "/home/travis/virtualenv/python2.7.6/lib/python2.7/site-packages/pandas/tests/test_tseries.py", line 344, in test_rank
    _skip_if_no_scipy()
  File "/home/travis/virtualenv/python2.7.6/lib/python2.7/site-packages/pandas/tests/test_tseries.py", line 16, in _skip_if_no_scipy
    raise nose.SkipTest("scipy not installed")
NameError: global name 'nose' is not defined`
```
 Ah, take that back with the "just remove last commit", I see one commit is there twice. I would either:
- create a new branch (from this one) and squish the commits (`git rebase -i HEAD~4`).
- create a new branch (from master) and cherry-pick the commits you want (`git cherry-pick commit_sha`).

Then push back here: `git push origin branch_name: CompatScipy -f`.
 @hayd Thank you for the bail-out. My local git is pretty well munged at this point... What is the best way to nuke it?  I've saved the "correct" copies of all affected files elsewhere so I can just drop them in. Should I just nuke the branches and do a fresh PR, or is there better way?
 I wouldn't nuke it just yet... create a new branch off master (assuming this branch was from there) and then drop them in or cherry-pick. You can then force push to this PR (using the code above), no need to nuke locally til it's successfully up here.

That is:

```
git checkout master
git checkout -b CompatScipy2
# do the stuff (either cherry-pick or drop in the files and commit)
# push your local branch to this PR with
git push origin CompatScipy2:CompatScipy -f
```

If it's up here ok, then you can go crazy deleting branches.
 @hayd Thanks for the bailout!!
 np! This looks great.
