rsplit ftw.
removed deprecated BaseException
Merge pull request #255 from riyadparvez/deprecated-removal

removed deprecated BaseException
Factor out HTTP(S)Connection -> ConnectionCls, and cleanup.

Also removed the need to None-ify global `ssl` module in tests.
New urllib3.connection module.
Merge branch 'factorout-connectioncls' of github.com:shazow/urllib3 into factorout-connectioncls