Implement more sane caret behavior

[cristeigabriela]

This implements a more sane behavior for caret movements, particularly for the Ctrl+Left/Ctrl+Right commands. This is somewhat similar to Notepad's, but better.

If you're hovering over a character that can be part of an address, we will progress one way or the other with the caret, until there's a character that's not part of the aforementioned predicate. The exception are the start or end of the textbox.

This is useful to quickly go over arithmetic, remove '`' from addresses that you get from WinDbg, etc.

It would probably be good to also implement Ctrl+Shift variation for Left+Right, and Ctrl+Backspace. I'm willing to do it if that's wanted (I may anyway, eventually).