small change to helicopter nose along with rotor
draw an animated tail roter but took it out because it looked bad
made ship health 3 instead of 90
made particle able to change colour
added damage states
made damage pixels all white and changes spawn rate
apply damage to roter
kill animation for ship and particle explosions when damaged
added particle bounce on edge of bounds
bullets explode on screen edges
update README
change ship limits so it cant go half off screen
added score model and multiplier
reset score multiplier when an enemy escapes
optimise drawj.js
small tidy up of effects.js
fixed stroke problem with draw.js
added extend() helper and used it from game_loop.js
added mouse click to input manager for fire
refactor of Input