Updated Selection Screen

I've updated the ship selection screen with much better/flasher UI and hopefully with more intuitive controls. There is now a ready-up button which, when all players select, will automatically start the game. 

Other updates/bug fixes:

• charge shot now has the correct scale/damage at all times
• missiles not reloading occasional is fixed
• updated overall player health to be a bit higher
• particle effects for strafe thrusters