LayerExplorer Constructor
        
 Create a Layer explorer.
 
         
        Parameters
        
            - layerManager
            
 
            - 
                
Type: dundas.controls.LayerManager
The layer manager for the layers. 
            - options
            
 
            - 
                
     Option object containing the following options:
     designerBackground [Default: null, type: HTMLElement] - the background of the designer.
     designerPlayground [Default: null, type: HTMLElement] - the playground of the designer.
     canvasContainer [Default: null, type: HTMLElement] - The DOM object that contains the designer.