Add Java port

Porting the latest version of the compiler and the VM to Java, using JavaCC for the parser
generator (without any AST generator library, instead building the AST
classes as classic POJOs).

Also porting the VM, and adding integration tests that cover 60% of the
generated parser code (no idea how much of the code is even reachable),
82% of the compiler classes and 95% of the VM code (code coverage
determined by cobertura-maven-plugin).


Might be a good idea to port the integrations tests back to Lua, but I won't do it :-)


It was fun to play a bit with your code, but this will probably be the last pull request by me.