todo list
import math into helper
allow finding the closes ready turret on the model, using arcade coordinates. allow firing a missile towards an arcade position.
fire a turret on phase 3 mouse clicks
add helper on the view to convert_screen_to_arcade coordinates
add purple color
ignore spamming event output with asteroid and missile movements
spawning of missiles from the closest ready turret via model
create a MissileSprite
create missile sprites in the view and move them along
remove missiles when they reach their destination
destroy missile sprites
rename arcade draw call
rename arcade draw variables
render arcade sprites in it's own panel
draw missile trajectories
add Explosion spawn, grow and destroy events
create an ExplosionSprite
create an Explosion model object
draw explosions