fix the processing of debug symbols and the related subpackage functionality (stable)

Backport from the IB/CMSSW_7_2_X/gcc491 branch:
  - update binutils and other packages for better support of debug symbols 

Backport #946 (support for debug symbols in scram projects):
  - generate debug information
  - relocate the source file information to a default directory (that GB can later remap)
  - split and compress the debugging symbols
  - package the debugging symbols in a separate sub-package

Needs https://github.com/cms-sw/pkgtools/pull/63 to be integrated before it can work.