Make grammar compilation available from within container

• ClassLoaders and hence the Java Compiler has no access to jars within a container
• Implementation in GTF based on http://atamur.blogspot.com/2009/10/using-built-in-javacompiler-with-custom.html and https://github.com/renatoathaydes/osgiaas/tree/f0e3d84f91bde64809e5fbe89ed30c6d9a43b0ab/modules/lang/osgiaas-javac/src/main/java/com/athaydes/osgiaas/javac/internal/compiler