Make changes, fix Travis CI build.

These changes to enable the Travis CI automated builds to pass.   A stable build environment allows more confidence in future changes, including adding back the 2.6 environment.  This build is spread over many commits as a consequence of testing Travis CI, but only touch four files:  .travis.yml, requirements.txt, setup.py, and README.md.

The changes made:
      Update Polygon2 to 2.0.6, as older version no longer available.
      Handle explicit download of Polygon 2, because it is not available from PyPi.
      Upgrade fontttools, which renamed from fonttools2.  Old version no longer available.
      Fix up setup.pys version_info  to not fail Python 2.6 (2008 version).
      Drop support for Python 2.6 anyway as new Polygon 2 does not support is.
      Check UnitTest output because it does not correctly set the exit codes status.
      Symbolically link vidle2 to vidle
      Fix some grammar in Readme.md.

Now Travis CI builds automatically on each commit.   The little graphic in the Readme.MD will list as "correct."