First draft of the Player game panel in ManageGamesMenu :
* can now add a Layout in a Layout
* Image can be scaled when it belong to a Layout
* correction of multiple bugs in Layout management (IND_Surface)
* creation of the Slider class
First draft of all menus in place :
* static part of Slider class working, but only with Images
* creation of the ChooseYourLevelMenu class
* link between each menu and the map / game
TODO : need dynamic links on players layers and level buttons + Slider drag and drop