Debugger merging

[giltho]

This is going to need a some of polishing first

A few notes, before or after merging this, one could:

• improve the different required signatures once and for all.
  For example, yes the GInterpreter needs some State.S, and the lifter needs more.
  We could split the State.S into ExecutableState.S and LiftableState.S for example, or whatever equivalent that sounds right.
  I would, at the same time, take care of the differences between Symbolic and Concrete states, to clear off all the "Failwith "does not exist for concrete states"
• Squash Wisl.CodeLoc with Gillian.Locations
• If we give-up the idea of having multi-threaded logged execution (which seems entirely faire), we don't need UUIDMs, and that could increase the speed of generating the reports