Changes

The automatic switch version of the multiface works by monitoring opcode reads from 0064 or 0065(for returning back to the stopped program) and 0066 and 0067 for entering multiface 2 ROM when pressing the stop button. There is a single call to 0065 (which has a RET) before the multiface 2 returns control back to the running program. The multiface 2 uses the stack inside the running program to return. It's not possible to activate the multiface ram and rom and call it 0064/0065 directly- it has no effect, the multiface 2 must be in a specific state (which happens when the stop button has been pressed) to accept the call and make itself invisible.