Updates and new computer added

Hey all, I've updated OmniPas again.  It has some updates, now includes Spectrum Next support, and some added new Spectrum units like 

• "spectrum_irq" - allows vblank waiting and updating a procedure each frame if you want.
• "spectrum_joy"  for joystick support (Kemston only right now; Sinclair 1 & 2 not working yet).