Adding a parser for veriT proofs.

git-svn-id: http://gapt.googlecode.com/svn/trunk/source@1561 85d21ef8-add0-11de-ae77-5bfb9c5a3f34
fixes bug in instance elimination algorithm for resolution proofs

git-svn-id: http://gapt.googlecode.com/svn/trunk/source@1562 85d21ef8-add0-11de-ae77-5bfb9c5a3f34