Added Openloops as a new external package.

Downloads all existing processes and compiles them.
- `openloops.cfg` contains gFortran flag needed.
- Compiles with -Os to try reduce the disk / memory footprint of those
  libraries.
Initial import of debug related files.
Merge pull request #1235 from ktf/backport-debug

Initial import of debug related files.
More backporting of debug subpackage support.
Merge pull request #1236 from ktf/backport-debug

More backporting of debug subpackage support.
Merge pull request #1178 from ktf/openloops

Add openloops external.
Merge remote branch 'origin/IB/CMSSW_7_3_X/stable' into IB/CMSSW_7_0_X/stable