This removes some modifications that the theories make to the simpset
and other global context, which slightly reduces breakage when importing
AutoCorres into other theories.
Unfortunately, some of the tests/examples seem to rely on specific
modifications to simp and wp, so removing those will be harder.
Also some simplification stages still seem to use the global simpset
instead of AUTOCORRES_SIMPSET; need to debug later.
Japheth Lim
Thomas Sewell
Lars Noschinski
Gerwin Klein