drools-compiler depends on antlr 2.7.7 and 3.3. Upgrade to antlr 3.4 to avoid having to depend on 2.x and 3.x at the same time

drools-compiler uses antlr 3.3 but has an additional dependency on old antlr:antlr 2.7.7 version.

The v2 dependency is obsolete since antlr 3.1 (see http://www.antlr.org/jira/browse/ANTLR-180).

Please remove the antlr:antlr dependency, for the next 5.2.x / 5.3.x release - thanks!