Build fixes for DRMAA, missing doxygen, and in general (files missing
in dist tarballs).
When debug is enabled, update CXXFLAGS in addition to CFLAGS.
Run "make distcheck" as part of CI builds.
Merge pull request #176 from mej/misc_build_fixes

Multiple Build Fixes for Master Branch
Merge pull request #177 from mej/travis_run_distcheck

Run "make distcheck" as part of CI builds.