* R5900 sky COP2 testing continuing. Today only small

* R5900 sky COP2 testing continuing.  Today only small
  VCALLMS-related were found/fixed.

[ChangeLog.sky]

	* sky-vu.c ({read,write}_vu_special_reg): Add CMSAR[01] as special
 	registers for a VU.  Behavior not as mandated.
	({read,write}_vu_{misc,special}_reg): Create sim_io_error upon
	access to unknown register.  Behavior not as mandated.

	* sky-vu.h (anonymous register numbering enum): Add CMSAR[01].

	* sky-libvpe.c (indebug): Cache $ENV{'SKY_DEBUG'}.

[ChangeLog]

	* Makefile.in (SIM_SKY_OBJS): Added sky-vudis.o.

	* interp.c (decode_coproc): Refer to VU CIA as a "special"
	register, not as a "misc" register.  Aha.  Add activity
	assertions after VCALLMS* instructions.