Add more options for program flow control

[anevilyak]

Currently, flow control is limited to run, step over, step into, step out, and breakpoints/watchpoiknts. In addition to these, it would also be nice to have a few more interactive options, such as being able to point to a line of code with the mouse cursor and asking to run to that point. The implemention shouldn't be that complex either, as this in effect simply necessitates setting a temporary breakpoint at said source location.

Another related but more complex feature that might be nice would be the ability to change the flow of control to a particular statement in a function, even one that's already been stepped over. The use case would be if, e.g. one has simply stepped over, and the return value was unexpected, so it's desired to execute said line again with a Step Into in order to understand why. This gets more complicated to implement however, since it may potentially mean changing the stack pointer and other cpu state attributes besides just the current instruction.

[anevilyak]

Run to cursor implemented in hrev45677.

[anevilyak]

Set next statement implemented in hrev45694.