2010-04-29 wenzelm 2010-04-29 proper context for mksimps etc. -- via simpset of the running Simplifier;
2009-01-21 haftmann 2009-01-21 dropped ID
2008-03-19 wenzelm 2008-03-19 eliminated change_claset/simpset;
2008-02-11 krauss 2008-02-11 Made theory names in ZF disjoint from HOL theory names to allow loading both developments in a single session (but not merge them).