ROO-3106: Spring Roo doesn't support new Java 7 language features

Added new implementation to utilize the antlr-java-parser library.  This may
eventually replace javaparser.

In this commit, the new changes are commented out (disabled) in the pom.xml file.  To test with the new library you must comment out references to javaparser and uncomment references to antlrjavaparser and antlr4-runtime.  There should be 3 such locations within the pom.xml file.