added lemma cpair_eq, made cfst_strict and csnd_strict into simp rules
added lemma cpair_eq, made cfst_strict and csnd_strict into simp rules

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