More extensive refactoring and questions on GameState StateMainMenu and (facade's) Terasology.java
Extensive refactoring of TerasologyEngine.java
Reduced refactoring compared to previous commit.
Reverted initAsset() and initConfig() methods to previous versions. Small tweaks here and there to comments and method descriptions.
Merge commit '42e6007' into develop

Conflicts:
	engine/src/main/java/org/terasology/engine/TerasologyEngine.java