TseitinCNF: fixed concurrency issue, TseitinCNF should now be threadsafe. Additionally added support for possibility to iteratively call TseitinCNF, by providing a way to pass a previous TseitinCNF object on to
the object, s.t. subformulaMap and atom blacklists are taken over.
Stopwatch: added toTuple support for CutIntroduction like output

git-svn-id: http://gapt.googlecode.com/svn/trunk/source@2323 85d21ef8-add0-11de-ae77-5bfb9c5a3f34
Utility Stopwatch: reverted last function definition, due to error.

git-svn-id: http://gapt.googlecode.com/svn/trunk/source@2324 85d21ef8-add0-11de-ae77-5bfb9c5a3f34