Add key click handler to Element

gfx/element.lua

@@ -13,7 +13,8 @@ local Element = {
   visible = true,
   dirty = true,
   id = "",
-  onClick = nil
+  onClick = nil,
+  onKey = nil
 }
 Element.__index = Element
 
@@ -203,6 +204,9 @@ function Element:handleEvent(evt)
   if Event.isClickEvent(evt) and Event.containsClick(self, evt) and self.onClick ~= nil then
     local x, y, source = Event.getClickParams(evt)
     return not not self.onClick(self, x, y, source)
+  elseif Event.isKeyEvent(evt) and self.onKey ~= nil then
+    local key, held = Key.getKeyParams(evt)
+    return not not self.onKey(self, key, held)
   end
   return false
 end