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 a start button
Renamed Enemy(Ship)Impl to SimpleEnemy(Ship)
Moved physics implementation to sub package, formatting code and removing unused imports.
Fixed test that relied on physics not being in a sub-package.
Merge branch 'development' into loadoutScreen.

Conflicts:
	Bullet-Inferno/src/se/dat255/bulletinferno/MyGame.java
Merge branch 'development' into loadoutScreen
Merging loadoutScreen into development
Fixed tests.
Merge branch 'development' of https://github.com/Jokab/Bullet-Inferno into development
Deleted SimpleEnemyShip
Dropped the Builder thingy. Didn't make enough sense.
Added weapon to SimpleEnemy and have it shoot in its constructor.
Enemies can now shoot. Timer isn't working though...
Enemies can now shoot properly (2 metres ahead of itself).
The enemy gets the weapon's timer and uses the callback to fire at the proper position.
Merged in team functionality