some changes to hlk

git-svn-id: http://gapt.googlecode.com/svn/trunk/source@1449 85d21ef8-add0-11de-ae77-5bfb9c5a3f34
enabled the sanity check for weak quantifier rules in lk again. issue 225 is now again unresolved, but the inference being made is really incorrect. will try to isolate a subproof where this happens.

git-svn-id: http://gapt.googlecode.com/svn/trunk/source@1450 85d21ef8-add0-11de-ae77-5bfb9c5a3f34