app: update user shortcuts to updated tools-value-[1-4]-* actions.

Commit 0bdb747 changed these action to more user-friendly names. Make
sure we update the user menurc to save any of their customization.
Implements Title bar codes for Layer dimensions

Implements codes %x, %y and %X, %Y to display
a layer's size in title and status bars
for image windows.
Addresses request at bug #728493