ui and graphics changes

* implement draw clipping using opengl stencil buffers
* allow to create Widgets by style name with g_ui.createWidgetByStyle
* styles can now have children widgets
* make proper use of the isNotPathable in pathfinding
* add scrollbar skin

modules/core_lib/globals.lua

@@ -12,27 +12,12 @@ function displayUI(otui, parent)
   return g_ui.loadUI(otuiFilePath, parent)
 end
 
-function createWidget(style, parent)
-  local className = g_ui.getStyleClass(style)
-  if className == "" then
-    error('could not find style ' .. style)
-    return
+function createWidget(stylename, parent)
+  if type(parent) == 'string' then
+    parent = rootWidget:recursiveGetChildById(parent)
   end
-
-  local class = _G[className]
-  if not class then
-    error('could not find widget class ' .. className)
-    return
-  end
-
-  local widget = class.create()
-  if parent then
-    if type(parent) == 'string' then
-      parent = rootWidget:recursiveGetChildById(parent)
-    end
-    parent:addChild(widget)
-  end
-  widget:setStyle(style)
+  local widget = g_ui.createWidgetFromStyle(stylename, parent)
+  --widget:setStyle(stylename)
   return widget
 end