Features added :
- select manager : allow the customization of the select manager (how many elements selected, how they are deselected)
- init select manager : allow the customization of the init select manager (how the elements are selected on init)
- init status manager : allow the customization of the init status manager (the status Open/Close on init)
- label manager : allow the customization of the label manager (the label for each tree element)
- tree manager : allow the customization of the tree manager (how to find the children elements for each tree element)
- set root elements : can add an element to the tree
- redraw : allow the tree to be redrawn
- elements are now unselectable/selectable
- walk : allow to walk all the elements of a tree