Replace the way too trivial config.h by RConfigure.h. The obsolete config.h

still exists for backward compatibility and just includes RConfigure.h.
RConfigure.h can now also be used in ROOT header files if needed.


git-svn-id: http://root.cern.ch/svn/root/trunk@16772 27541ba8-7e3a-0410-8455-c3a389f83636