Add an embodiment of the Omega d.p. for use inside the simplifier. It
can perform quite badly on goals with too many disjunctive assumptions
(and ~(x = y) counts as a disjunction).

Added a whole bunch of useful rewrites for the stateful rewriter to
integer theory. A tactic in DeepSyntaxScript need slight modification
because of the change.

Total reorganisation of Cooper code. Two ..Core modules can be swapped
in and out of CooperShell to provide "shadow syntax" or my original
implementation of the core phases of the algorithm. Code currently littered
with profiler guff.