added separate freeVariables / boundVariables methods to lambda calculus

git-svn-id: http://gapt.googlecode.com/svn/trunk/source@1500 85d21ef8-add0-11de-ae77-5bfb9c5a3f34
added some test case files, introduced methods freeVariables and boundVariables and replaced getFreeAndBoundVariables

git-svn-id: http://gapt.googlecode.com/svn/trunk/source@1501 85d21ef8-add0-11de-ae77-5bfb9c5a3f34
Implemented a shallow function for multi-expansion trees. Delete some empty directories. Organized the imports in cli.

git-svn-id: http://gapt.googlecode.com/svn/trunk/source@1502 85d21ef8-add0-11de-ae77-5bfb9c5a3f34