Minor coding style cleanups
Add rationale for the approach to README
Clean up and simplify standard_library_renames
Add tests for standard_library_renames
Improve str_is_unicode module and tests
Add simple test autodiscovery
Fix up tests so they can be auto-discovered and run
Add first attempt at .travis.yml
Remove executable flag from six.py
Add docs and tests about 'from future import *'
Skip some tests known to fail

- "from future import *" seems to work, but not together with unittest. Perhaps
unittest is inserting itself in the frame, breaking the use of inspect to grab
the previous frame.

- Tests involving automatic running of code generated by 2to3 aren't yet
  working either ...