Added support for negative offsets in register-indirect with offset addressing ( like SET a, [b-10] )
changed IRQ handling to always execute interrupts AFTER a command has been executed
(this fixes weirdness during single stepping over INT instructions where
the execution would continue and jump to the IRQ handler when stepping the instruction
following the INT)
fixed bug in SBX ; EX was not set correctly on underflow
preparations to make more emulation options configurable through the UI
Added menu item for configuring emulation options like debug level, memory protection etc.