code: function followControl( controlRef ) {
        return resolveRef( join( controlRef, 'control.json' ), paths.controls )
           .then( descriptorPath => readJson( descriptorPath ).then( control => {
              const path = dirname( descriptorPath );
              const name = control.name;
              const controls = control.controls;
              if( !name ) {
                 return Promise.reject( 'Control descriptor is missing name: ', path );
              }
  
              return [ {
                 refs: [ controlRef ],
                 name,
                 path,
                 descriptor: control,
                 category: 'controls',
                 schemas: [ 'control' ],
  
                 controls
              } ];
           } ) );
     }
docs: ///////////////////////////////////////////////////////////////////////////////////////////////////////// 
  Collect meta information about a single control.
  
  @private
  @memberOf ArtifactCollector
  @param {String} controlRef the control reference (relative to `paths.controls`) to follow
  @return {Promise<Array>} a promise for an array containing meta-formation about a single control