Restructured to allow the use of multiple screens.
Changed MyGame to implement Game.
Moved the render, resize, ... logic of MyGame to a new class GameScreen. GameScreen will now function as the "main controller" for the running game.
Added an abstract class AbstractScreen, for basic shared handling of (mostly) menu-like screens.
Added a new class LoadoutScreen.
Merge branch 'development' into loadoutScreen
Merge branch 'development' into loadoutScreen
Set up a (very) basic first attempt at a menu.
Merge branch 'development' into loadoutScreen

Conflicts:
	Bullet-Inferno/src/se/dat255/bulletinferno/MyGame.java
Added PhysicsWorldSpy test class.
Changed to Bullet Inferno Formatter for test eclipse project.
Added return value to physics world spy createBody call.
Now using the physics world spy in SimpleMockGame.
Added projectile tests for collisions with projectiles and playerships.
Changed physics spy in SimpleMockGame to concrete type for easier testing.
Added a start button
Changed ProjectileImpl to conform to test: damage is set to 0 when hitting something.
Testing the create-collide-remove flow of a projectile in the physics world.
Fixed projectile tests: Projectile.init and Projectile.reset must be called since projectiles are poolables.
Adjusted tests accordingly.
Formatted ProjectileImplTest.
Added test for EnemyImpl and corrected some code in it
Merge branch 'collisionTest' of https://github.com/Jokab/Bullet-Inferno into collisionTest
Merged in test of enemy
Implemented the rest in enemyImpl test
Merge branch 'collisionTest' into development
Merging in collision tests