code: function getChildByType(_class) {
           var objList = [];
  
           for (var i = this.children.length - 1; i >= 0; i--) {
             var obj = this.children[i];
  
             if (obj instanceof _class) {
               objList.push(obj);
             }
  
             if (obj instanceof me.Container) {
               objList = objList.concat(obj.getChildByType(_class));
             }
           }
  
           return objList;
         }
docs: returns the list of childs with the specified class type
  @name getChildByType
  @memberOf me.Container.prototype
  @public
  @function
  @param {Object} class type
  @return {me.Renderable[]} Array of children