Use different gcc version in OS X to calculate coverage.
Install lcov for test suite coverage checking in OS X and Linux.

Fixed #29.
Check for existance of lsb_release in Linux when bootstrapping.
Merge branch 'next' into coverage-bootstrap
Check if existing MPIDE_DIR actually points to something.
Remove unused test helpers file.
Merge remote-tracking branch 'origin/coverage-bootstrap' into coverage-bootstrap