CPU:
- Stack operations and stack support in general
- Subroutines
- Comparisons and branching
- LDY and LDX must behave properly in 8-bit mode when x bit in the p status 
  register is set to one
- Accumulator must behave properly when in 8-bit mode
- Emulation mode support in general.
- Have each operation return the number of cycles used by the execute function.
- Implement the rest of the missing operations.
Memory:
- Banks
- ROM protection
- Memory mapped I/O
Display:
- Using the html page included provide a nice interface for using the cpu 
  emulator and provide many features helpful for debugging