Add ability to pause and resume the program from both the GUI and via code

[monkeyman192]

Often when investigating some function, it might be nice to pause the program state so that if the state doesn't stay that way for very long, another program like Cheat Engine could then be used to look at the memory while paused.

This should be possible both as a button in the GUI (pause/resume), as well as from code in some way (decorator to allow some functionality, as well as a function which can be exposed to do this)