CutIntroduction: refactored imports, merged NCutIntroduction into CutIntroduction, refactored TODOs


git-svn-id: http://gapt.googlecode.com/svn/trunk/source@2115 85d21ef8-add0-11de-ae77-5bfb9c5a3f34
(commented the test for prover9 in acnf computation) added size methods for structs and expansions trees. added skolem quantifiers to expansion trees. lksk tests are still missing.

git-svn-id: http://gapt.googlecode.com/svn/trunk/source@2116 85d21ef8-add0-11de-ae77-5bfb9c5a3f34