Merged latest opcode changes by Ferry.
Merged Maria's RSC code into Core.rsc
Implement interfaces/class distinction.

Merged latest Opcode changes.
Merge branch 'master' of https://github.com/FerryRiet/Rascal-clone

Conflicts:
	src/org/rascalmpl/library/lang/java/m3/Core.rsc
	src/org/rascalmpl/library/lang/java/m3/internal/JarConverter.java
Fixed createM3FromJar (crawl thing, removed redundant code, replaced some code by a comprehension :D).

Seems to work properly on my end. Please verify ;)