The `commands` line was accidentally(?) removed entirely in
57f716ed, so tox no longer actually ran any tests (only flake8).
This restores it, with the codestyle bit removed obviously. It
also fixes two lines where a tab was used instead of spaces.

Signed-off-by: Adam Williamson <awilliam@redhat.com>

This fixes tests not being added to the source package.

I did this kind of on personal interest, since my emacs (using flake8)
marks every violation (meaning: line >79 chars) red, which is pretty
annoying.

I personally think 90 is a realistic guideline.

Remove python2.6 from
- Travis
- Tox
- PyPi tags
- documentation and readme

Also, Simplify an import clause.

This fixes #133

Should at least be compatible with Python 3.4 now.
Can't get Python 3.3 to work locally, but let's see with Travis.

- For some reason, 'pytest-cache' isn't found by setup.py if not
  specified explicitly in 'tests_require'
- Add tox.ini so tests can be run using tox if desired
- Update test to not be dependent on serialization