Alter Mode. Eval word . Improved Signature. Renamed Loop -> Times. Added Empty.

* Alter mode: Runtime + Meta but return data to current block instead of
RStack.
* Signature : can split the 2nd half into , again, signature.
* Loop -> Times for readability .
* Empty : mean void Word argument.
* Added Push / Pop / Rot ( actually ROT and SWAP are not core function &
can be defined in runtime)
* Removed Open/Close Brace
* Word out params is determined by last word return params & type.