Features and bugfixes in v0.4

• Added new tile artwork for some beginning rooms
• Separated the command buttons from contextual action buttons, so that they are clearer
• Added hotkey displays to all buttons.
• Added basic XBox controller support (not complete yet)
• Two new mechanisms: Laser and Proximity sensor triggered doors
• Added menus to navigate around in the game
• Added Pause menu to respawn or reload any previous checkpoint
• Fixed one performance issue which should improve FPS