added gun sprite with simple rotation animation
set rotation center to begin of gun
added support left rotation
added gun class sceletone
added rotation method and constructor
fix names in createBackground method
fix name
fix rotation velocity
fix gun position
fix gun position again
add rotation constraints
add method to find bullet start position
fix constants
add getGunAngle method
add testFireMethod and correct getShootStartPoint method
refactor constructor
refactor events
fixed bug with shoot and rotate gun at same time
 delete empty lines
 delete empty lines