Various updates mostly capability related :

* Added pretty printing for capability instructions
* Added debug print functions
* Added dump of the capability registers on MTC2 selector 6
* Added custom exception handler address for CCall and CReturn traps
* Correctly set the CP0 config1 register telling the presence of a CP2
* Turned signed comparisons to unsigned ones for comparisons with PIC
  addresses
* Fixes in capability instructions exception checkings