Cursors and Bitmaps

Two changes today. I’ve optimised the MultiLineTextBox’s cursor drawing routines. It’s not as fast as it could be - the fastest way to draw it would probably be to inject it into the main drawText() routine - but as that class changes so much I think it’s best to keep it readable at this stage.

Secondly, I’ve replaced the Bitmap struct with a Bitmap class. The struct wasn’t being used anywhere. The class includes all of the drawing functionality previously only available in the SuperBitmap, so it is now possible to create and manipulate bitmaps entirely in memory without an associated gadget. This should, I think, answer one of Jeff’s earlier queries. I’ll get around to stripping the code from the SuperBitmap and replacing it with the Bitmap class later. Not sure if the SuperBitmap is going to inherit from the Bitmap or just contain an instance of it yet.