Cleanup dependency and unused files

https://bugzilla.redhat.com/show_bug.cgi?id=1067288
Size of WAR file
before: 102.5MB 
after: 98.6MB
Unfortunately, I had to put back the dependency on the antlr module, otherwise I get ClassCastException when running inside jboss.

There seems to be no way of telling Maven that antlr is provided, without also hard-coding the version of antlr.  Why can't Maven just use the version of antlr requested by our other dependencies?  Another option would be to import droolsjbpm-parent like a bom, but then we'd just have to hard-code the version of drools!