Port of Epoch Galaxy II for MiSTer FPGA

Remap game buttons and use the skill level select for game mode.

From original user guide:

• Skill Level "1" - Alien fighters attack one at a time.
• Skill Level "2" - Alien fighters attack one at a time but combat speed is faster.
• Skill Level "3" - Alien fighters attack two at a time.
• Skill Level "4" - Alien fighters attack two at a time but combat speed is faster.

When game is switched on, skill level is automatically set to Level "1" and "1" is displayed at top of Game Display.