Add mouse binding pointer position configuration

Add the `--whole-window` switch for mouse bindings. This switch controls
what part of the container the pointer must be over to trigger a mouse
binding. The default is to only trigger mouse bindings over the
titlebars. With this switch, a mouse binding will be triggered over the
main part of the window as well.

This is a breaking change to the previous behavior, which would trigger
a mouse binding with a modifier over any part of the window.

fixes #1429

include/data.h

@@ -255,6 +255,11 @@ struct Binding {
         B_UPON_KEYRELEASE_IGNORE_MODS = 2,
     } release;
 
+    /** If this is true for a mouse binding, the binding should be executed
+     * when the button is pressed over any part of the window, not just the
+     * title bar (default). */
+    bool whole_window;
+
     uint32_t number_keycodes;
 
     /** Keycode to bind */