Fixed Sprite Issue and Games Not Loading Issue

- (Games not loading issue) Second program bank was not being read into
memory causing the Program Counter read from FFFC/FFFD to be invalid.
Added code for second PRG Bank.
- (Sprites not working issue) Fixed problem with 0x91 (STA) instruction.
bLow and BHigh were char and not unsigned char.  Once I changed them to
unsigned, the sprites stopped flickering.
- Added Right mouse button click to displayMenu/!displayMenu.