Explicit python2 invocation
Bypass clang error

See http://bruteforce.gr/bypassing-clang-error-unknown-argument.html
Merge pull request #412 from ged-lab/fix/jenkins-osx

Bypass clang error
Merge pull request #404 from ged-lab/fix/python2

Explicit python2 invocation
fixed thread hanging issue khmer#384
fixed spelling error