twoplayer v0.4.0

• Both players can now enter their high score
• Player 2 can now press A to enter two-player mode. Player 1 can now start the game for Player 2 by pressing Start. If Player 2 is holding A when the game is started then their level will increase by 10, independent of which player pressed Start. This should allow the Famicom Player 2 controller to be used, which lacks a Start button