Enhancements to BASIC including:

• Implementing UNPLOT X,Y
• Implementing CLS for DISPLAY 2 mode
• Fixed COLOR function to update background color register
• Disabled kernel console interrupt during DISPLAY 2 mode

New BASIC example programs:

• leaf.bas: Generate a "Barnsley Fern"

• draw.bas: Etch-a-sketch style drawing program using the NES controller