Subcanvas: first graphics.

A screenshot:


 
What is it? Well, it's an orange line, green rectangle, filled blue rectangle and small blue bit of text. The relevance here is that I've gotten some basic graphics output from Subcanvas.

The features that you aren't seeing here are:

• The code for this is in a Package, and the classes are all in Namespaces. Namespaces really work! Although... I have found some more nasty bugs that destroy code.
  
• The coordinates used are measured in micrometers. Those are 20mm by 20mm boxes on my screen, roughly.

My next steps are to add support for child canvases and keyboard / mouse event handling.