wbox: Make :find_widgets() easily accessible

Signed-off-by: Uli Schlachter <psychon@znc.in>

lib/wibox/init.lua.in

@@ -48,6 +48,16 @@ function wibox:set_fg(c)
     self._drawable:set_fg(c)
 end
 
+--- Find a widget by a point.
+-- The wibox must have drawn itself at least once for this to work.
+-- @param x X coordinate of the point
+-- @param y Y coordinate of the point
+-- @return A sorted table with all widgets that contain the given point. The
+--         widgets are sorted by relevance.
+function wibox:find_widgets(x, y)
+    return self._drawable:find_widgets(x, y)
+end
+
 for _, k in pairs{ "buttons", "struts", "geometry", "get_xproperty", "set_xproperty" } do
     wibox[k] = function(self, ...)
         return self.drawin[k](self.drawin, ...)