Phs/mk 123 make ruby java api for serialization

Expose a codec API in `Type.encode` and  `Type.decode`, which converts plain ruby objects to and from java byte arrays as directed by an askari type.  It errors where it needs to, but not in a particularly pretty way.

Buyer beware!  `Type` has grown too large but I haven't broken it out into a subdirectory yet, as we're on a deadline.