remove_unsafe_private_use isn't necessary in current Python.

As of Python 3.3.3, the bug that made `remove_unsafe_private_use`
necessary is fixed. The function will remain there, but it's not used as
a part of the `fix_text` process anymore.

Along the way, added more comments and expanded docstrings.
add the streaming Twitter tester
Merge branch 'streamtester' into fix_ellipsis