add polib to python-packages
remove nonexercise metadata from exercise po files before concatenating them
remove subprocess.check_output for the sake of py2.6 compatibility
fix the removal of nonmetadata
Merge remote-tracking branch 'refs/remotes/upstream/develop' into 1244
don't use -i since that's only for GNU sed
cleanup of unused function; documentation and fixing of messages
Merge branch 'develop' of github.com:learningequality/ka-lite into 1244
tweaks to po file filtering
Merge pull request #1261 from aronasorman/1244

Process only relevant KA exercise po files