First steps in splitting wkpf in a part without vm and separate wkpf_virtual library that adds support for virtual wuclasses on top of it. Committing because I decided to split the heap code and keep the GC in core since wkpf depends on it too much, and I want that change in one clean commit.
Splitting garbage collector into generic part in src/core and vm specific code in lib/vm. Still broken at the moment.