* PKE sim unit testing continuing. The DIRECT and MPG instructions

* PKE sim unit testing continuing.  The DIRECT and MPG instructions
  were hammered in today's runs.  Work is beginning in endian-proofing
  the code.

	* sky-pke.c (pke1_issue): Issue on correct PKE device.
	(pke_io_write_buffer, pke_code_mpg, pke_code_unpack): Perform more
 	endian conversions.
	(pke_code_mpg, pke_code_direct): Add operand alignment assertions.
	(pke_code_mpg): Correct VU stall checks.  Correct VU opcode
 	transfer ordering.
	(pke_code_direct): Correct typos in DIRECT operand accessing.
	(pke_code_unpack): Correct conditional sign-extension handling.

	* sky-gpuif.c (gif_io_read_buffer, gif_io_write_buffer): Correct
 	assertion polarity.
	(gif_read_tag): Disable faulty DMA-tag testing code.