README updated, commented out failing test.
Bumped release.
Travis ci matplotlib gui fix.

Thanks to
http://ryanvarley.co.uk/solutions/2014/05/14/how-to-solve-travis-ci-matplotlib-tclerror-no-display/
Now using print function in all tests.
Fix for python 2/3 compat with zip.
Merge branch 'master' of github.com:jgoppert/python-control