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
set default include dir, so that running tests from source works at least in most linux distros
add install step for tests that run external autogenerated code, and need cffi
#21 - try to test against postgres 9.3, should have better control over notices
#21 - fix bench command
#21 - only 5 runs of benchmark
Merge branch 'master' into psycopg1