Reworked build-DB method... needs more testing
Much easier rescan/rebuild with unified function

Still get warnings about headers being re-added when I execute a
rebuild, which is likely to flood the log file.  But when I clear the
headerMap_ I end up segfaulting... a little more work to do there...
Rescan/rebuild work on C++ side!  Now integrate w/ GUI
Merge rrld_planB (desktop) into rrld_planB (laptop)

Conflicts:
	cppForSwig/BlockUtils.cpp