Now parses Myco code and generates an AST (albeit _very_ slowly)
Disable loading and executing the Myco grammar for now to speed up tests
Added BytecodeInstructions and BytecodeMachine

--HG--
extra : amend_source : ae421bff878c032f918c9c05735425b025f8054f
Borrow bytecode generation methods from Pegarus instead of
trying to follow the low-level LPEG instructions -
they don't map easily onto the Rubinius VM without a lot
of bother tracking labels between instructions.

--HG--
extra : amend_source : eae27caa6b6b6d2adfc2cbdd6ac73d266ae53349
Implemented BytecodeInstructions#set

--HG--
extra : amend_source : a91013fa5b225a1dd69a8be9bd3c38bf8e71daf4
Added BytecodeInstructions#kleene
Fix bug with BytecodeInstructions#set with subject.at(idx)==null
Added BytecodeInstructions#many

--HG--
extra : amend_source : f2f86013efab5ceec2b10c16a643959430953057