Make explicit assumption of disjointness of free list and live cells
Implementation of Armstrong/Virding (need to put in assertions)
Move out root handling to a separate module, whichc an then be used by Fenichel/Yochelson
Implementation of Fenichel/Yochelson (with no asserts yet)
Implement linked list functions for demo
Implement small test program and fix a couple of bugs in the collectors (I haven't C'd in so long :() - next step, checked assertions!
Implement assertions for Armstrong/Virding and expand the test program a bit: fix revealed bugs in implementation of lists and GC (managing your own roots is hard...), and fix a few overzealous >=s in dissertation