Added <registers/> command.
Lots of development of Cell/HeapObject to improve the programming style. Integration into gvmtest.
Added MapObject and it's internal MapObject::Generator class.
Further improvement to the Cell & HeapObject, plus minor bug fixes.
Merge remote-tracking branch 'origin/master' into gvmtest

Conflicts:
	apps/gvmtest/cpp/gvmtest.cpp
Fix missing public: section in MapObject.