Implement possibility to cancel run-command, when processor ran into loop

[croesch]

At least when you are running a program the user should have the opportunity to cancel running the program and step back into the debugger's menu again. Currently this is not possible and the user has to quit the debugger if the program ran into a loop.

So at least when running (maybe stepping) through the micro/macro code the user should have the opportunity to cancel the running command, the only way this might be possible, might be with another thread.

Another possibility would be to give a configuration entry that says how many ticks can be done at maximum. So that if the processor runs into a loop it executes just the maximum of ticks and the user has access again.