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.
Move to root 5.34.22.
Drop unneeded llvm patches.
New xrootd 4.0.4

- Move to new version.
- Cleanup obsolete patches.
Move to new boost 1.57.00
Merge pull request #1212 from ktf/update-7-4-x

Updating key externals for CMSSW_7_4_X
updated icc compiler to 15.0.1
Merge pull request #1222 from smuzaffar/IB/CMSSW_7_4_X/stable

updated icc compiler to 15.0.1
Move to igprof/igprof@27fa22fe00391bb494b6c8012c5a8a664fecff74 (i.e. v5.9.12)
Merge pull request #1231 from ktf/new-igprof

Move igprof to v5.9.12
Update to new version of thepeg.
Merge pull request #1232 from ktf/new-thepeg

Update to new version of thepeg.
Initial import of debug related files.
Merge pull request #1235 from ktf/backport-debug

Initial import of debug related files.
Merge remote branch 'origin/IB/CMSSW_7_3_X/stable' into IB/CMSSW_7_0_X/stable
Merge remote branch 'origin/IB/CMSSW_7_3_X/gcc491' into IB/CMSSW_7_0_X/stable
More backporting of debug subpackage support.
Merge pull request #1236 from ktf/backport-debug

More backporting of debug subpackage support.
upgrade to rivet 2.2.0 and yoda 1.3.0
Merge pull request #1237 from mkirsano/torivet220

upgrade to rivet 2.2.0 and yoda 1.3.0