fixed bug where nothing would show if order was added after one had been removed.
made some coordinated constants for easier editing and referencing.
removed redundant oldTarget variable.
added button availability
made full game button unavailable.
changed the way alitmeter was drawn to fit aesthetic.
fixed -1 indexing bug occuring because of ripple().
moved manual control from aircraft to demo (to allow more than one way to change direction - keyboard and GUI).