Fix two minor style things.

There is a pep8 indentation issue and an unused import. Fix them here
so I can verify that my later patches don't regress and become unhappy.
Fix exception handling error.

The exception handler was passing an exception object to the unicode
function, which was not causing it to stringify.
Add a few more backwards compatibility options.
Move setup_requires to setup_requires_dist.

In anticipation of pep-426
Remove extra complexity of six.u wrapper.
Merge pull request #24 from emonty/small_fixes

Small fixes