Moved meta simplification stuff from Thm to MetaSimplifier.
Moved meta simplification stuff from Thm to MetaSimplifier.

MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle