ol-ext: control Toggle

ol.control.Toggle is an ol.control.Button with an active/deactive state.
If can be created with an ol.interaction and controls its activation.
It can be grouped into an ol.control.Bar with a toggleOne propertie to have only one activated at a time. You can compose toolbars with it (see the control bar example).
When adding Toggle control to a bar, an option bar can be nested to add a subbar visible when the control is active (see the sub-bar example).