V 1.00 Initial release

v 1.01
  Changed so that the graphics are now handled by the os for different screen modes
  When EX0 EY0 was used the main window was redrawn at half size.
  
  Rather than adapting the program to cope with this mode which would mean 
  allocating more memory for graphic conversion I have changed the program
  so that it uses a back canvas graphic in the same format as all the other 
  graphics and fast plots using SYS  "OS_SpriteOp", 256+34 all graphics to this 
  back canvas and the uses the slower SYS "OS_SpriteOp", 512+56 to convert the
  final graphic to the screen mode.

v 1.02

	Removed Yredraw only one size size was confusinf EX0 EY0 screens
	screen size is 1280 x 960 (640x480 pixels)