Simplify interpreted language:

Simplify interpreted language:

- Expand operand argument specifiers so that all registers and
  parameters can be referenced directly.  Remove old PAR/PRL
  instructions.

- No 3 operand instructions, translate MAD -> MUL, ADD.  (No room for
  3 full operands in instruction struct).

- Translate SWZ instructions into 1 or 2 reduced swizzles at compile
  time.

- Add hardwired code for moving input and output values to/from the
  register file.  Drop old INx, OUT instructions.