Merge pull request #348 from hwoarangmy/development

Added the keeper hand + slap
Merge pull request #351 from hwoarangmy/development

When the XP table is overriden in a level file, it should be written by the editor when the level is saved
Applyed code conventions to Tile class + code cleaning
Added all GameEntities that can be in a tile to one list only to make code more generic
+ a bit of code cleaning