Implemented back button in AboutScene

A back button is added and implemented in the AboutScene.java class
Implemented back button in RankingsScene

A back button is added and implemented in the RankingsScene.java class
Implemented back button is BadgesScene

A back button is added and implemented in the BadgesScene.java class. Also some code is modified for the looks
Implemented back button in StartScene

A back button is added and implemented in the StartScene.java class
Removed unused code

The inner class BackButton wasn't used so it is now removed
Implemented Weapon Upgrade Trap

For testing purposes all traps are set to trigger a
upgrade_weapon_trap. This must of course be changed back  in the
ultimate end of change requests.. that also means for each other change
requests regarding new traps, this same approach should be used to
actually test if the trap works.

* IGNORE * I’m like chocolate. Delicious. Also I feast upon all kinds
of dirt.
Removed food and hunger system
New window implemented

The new window has been implemented, with the Hero being able to quit
the game if he is a chicken in the first level.
Removing food and hunger system
Merge branch 'BackButton'
Merge branch 'Anders'
Merge branch 'Hero-Is-A-Chicken'
Merge branch 'RemoveFoodHunger'