code: function addonsManager_enableAddon(aSpec) {
      var spec = aSpec || { };
      spec.button = "enable";
  
      var button = this.getAddonButton(spec);
      this._controller.click(button);
    }
docs: Enables the specified add-on
  
  @param {object} aSpec
  Information on which add-on to operate on
  Elements: addon - Add-on element