ol.control.Bar can be nested in a sub-bar using an 
ol.control.Toggle to control its activation.
    
      - 
        toggleOne option makes only one control activated at once.
      
- 
        autoDeactivate option will deactivate all controls in the sub-bar when this is deactivated.
      
    Options of the 
ol.control.Toggle enables the sub-bar activation:
    
      - 
        Use the bar option of the ol.control.Toogle to set the sub-bar you want to display.
      
- 
        The autoActive option enable you to automatically activate a control when the sub-bar is shown.