New projectiles get spawned at the nozzle of the turret by default

The direction is set to the direction of the turret at that time as
well.
Added a package for the weapons.
Added ImageHandler-class.
Made each projectile aware of which tank that fired it. Also added preliminary collision handling for projectiles.
World now has a size
Added MapBounds class
New worlds now adds a MapBounds automatically
Made the tank bounce when it hits the edge of the map.
Projectiles are removed if they hit the edge of the map.
Projectiles now destroy themselves
Removed old code for removing and destroying projectiles
Working on imghandler...
Reworked Play's update() and render().
Added different sprites for different projs.
The AbstractPowerUp now keeps track of effectDuration and when the effect is active.

The class comes with two abstract methods that needs to be added into
the specific powerup class, what happens when it's applied and what
happens when it runs out.
Added two (2) powerups: FireRate and Speed.
The tank now keeps more accurate track of when a powerUp is applied, and takes care of it.
Changed the fireRate in flamethrowerTurret to 32 (from 1) so that the fireRatePowerUp will have an effect.
A powerUp for increased damage, work in progress!
Projectiles now remove themselves from their Tank's list of projectiles when they get destroyed