+ Added some javadoc to the SlickUtil class
Merge branch 'develop' into feature/Doc-Slick2D
+ Finished adding javadoc to SlickUtil
* Fixed javadoc issues
+ Added documentation for all the GUI-related classes
+ Added javadoc for State and Game, finishing adding the javadoc to the Slick2D module
Merge branch 'feature/Doc-Slick2D' into develop