Improved the build matrix.
Run the benchmarks after each build. Fixes #21.
Merge branch 'thedrow-patch-1'

travis.yml improvements: Improved build matrix, post-build benchmarks
#26 - 3.x and pypy3 will have to wait for py3 branch
Merge branch 'master' into py3
#26 - readd 3.x and pypy3 to travis.yml