blockMesh: most mesh data are now demand-driven

- Unless the points(), cells(), patches() methods are called, the classes
  should know maintain a lightweight representation for as long as possible.

- bugfix: old-code used xferMove() instead of xferCopy() when creating the
  topology mesh - causing const pointField& to break if the code order was
  changed

- relocate blockMesh from src/meshing -> src/mesh

applications/utilities/miscellaneous/foamDebugSwitches/Make/options

@@ -39,4 +39,5 @@ EXE_LIBS = \
     -lthermophysicalFunctions \
     -ltopoChangerFvMesh \
     -ltriSurface \
-    -lautoMesh
+    -lautoMesh \
+    -lblockMesh