Work on the Gui: some of the framework for drag & drop. Also made Window an IWidget. Implemented getWidget(x,y) to find the widget under this location for IWidgets (but not Gui). Made Window an IWidget and made it work a little more similarly to widgets. Implemented callbacks on the Gui for mouse events (enabling drag & drop, etc.). committer: Diggory Hardy <diggory.hardy@gmail.com>

{MT01}
<char[]|Renderer="Simple">
{W1}
<int|x=30>
<int|y=80>
<int[][int]|widgetData=[0:[1003,200,200]]>
{W2}
<int|x=150>
<int|y=200>
<int[][int]|widgetData=[0:[1002,1,3,2,3,5],2:[1001,150,150],3:[1003,150,150],5:[1002,2,1,6,7],6:[1003,73,73],7:[1003,73,73]]>