Add @DirtiesRuleSession annotation for test methods and classes

[dabdine]

The annotation should perform a reset() on the rule session, and only apply to StatefuleRuleSession annotated test classes. More specifically, the annotation should invoke the RulesJUnit4ClassRunner to invoke reset() on the StatefulRuleSession whenever a method is encountered that is annotated with @DirtiesRuleSession, or for every method if the test class itself is annotated with @DirtiesRuleSession.

This doesn't apply to test classes that use StatelessRuleSession and should cause an error condition if @DirtiesRuleSession is used in any situation while a StatelessRuleSession exists in the test class.