add missing function to check vc configuration
Changed the xrootd and builtin_xrootd  (to version 3.3.6) to fix the problem with stressProof in nightlies
As usual, nobody cares about Windows...
Enable cocoa by default on MacOSX
Fix memory leak (ROOT-6116).

(cherry picked from commit cda6480dd28f6d75406f8e3351644a8a7c7783cb)
Enable by default cocoa if OSX version > 10.7. Remove some warnings.
Fix in PROOF doc
Added dataset staging functions to PROOF-Lite
CPU pinning on Linux for PROOF-Lite
AliEn ds can cache site storage endpoint URL