remove mpi from explicit profile dependencies
fix MACOSX_DEPLOYMENT_TARGET for OS X > 10.9

regular expression only caught first digit of minor version, turning 10.10 into 10.1
Merge pull request #597 from minrk/osx-pattern

fix MACOSX_DEPLOYMENT_TARGET for OS X > 10.9
Merge remote-tracking branch 'origin/master' into ahmadia/parametrize_scipy_tests