Ticking the cpu does not check for break points

If the user chooses to step e.g. 100 ticks and a breakpoint is reached on tick e.g. 30, the CPU will not signal this. A check for break points needs to be added in the method do_tick() in core/processor.py, much like in the method run_continuously().

Moreover, the thread in the GUI for ticking the CPU does not stop for halts or break points when running a specified amount of ticks.