Debugger better mouse support

[Michaelangel007]

UPDATE: This PR is not yet done as I have been cleaning up some LONG over-due re-factoring.

~~Please merge #785 first to prevent previous commits from showing up.~~

• [x] # 785 Merged.

This adds support to the debugger for:

• Middle, Forward, and Backward mouse buttons
• cleanup to support the 5 buttons in a nicer fashion. DebuggerMouseClick() -> DebuggerProcessMouseClick() (to be more consistent with the keyboard handler: DebuggerProcessKey()`
• Ctrl - goto previous bookmark
• Ctrl + goto next bookmark
• Backward mouse button. This is goto previous bookmark.
• Forward mouse button. This is goto next bookmark.

~~NOTE: Frame.cpp might appear to have the mapping backwards but this is intentional. This is because on my Logitech mouse:~~

• the Forward button is further away from me -- this defaults to next page on a web browser. This mapping doesn't make sense in a vertical listing where "forward" means lower in Apple memory (top of the screen), and
• the Backward button is closer to me -- this defaults to prev page on a web browser. This mapping doesn't make sense in a vertcial listing where "backward" means higher in Apple memory (bottom of the screen):

Currently the commited code has this ...

			if (wparam & MK_XBUTTON1) button = MOUSE_BUTTON_BACKWARD;
			if (wparam & MK_XBUTTON2) button = MOUSE_BUTTON_FORWARD;

... but in reflecting upon this I will make another update so it is less confusing as the forward/backward buttons are going to be used for other things as well -- specifically an Address History.