Every architecture was at least slightly wrong. Rather than try to
tune the heuristics, let's just keep lists of all the registers.
Also start adding some unit tests.
Change-Id: I490dcc9855f7af1e3529734711400f366ffc4e0f
This includes the fairly large change of refactoring stack_core.py into
a class so that its behavior is compatible with adbs. Additionally, if
the ABI line does not come before lines that require it to determine
proper widths (registers, stack), then it will assume that the ABI is
32 bit and not 64.
Change-Id: I6ad84a55337d86d25f7f8197048dc93868b0a01a
