code: function defineEnumProp(obj, key, value) {
          Object.defineProperty(obj, key, {
              value: value,
              enumerable: true
          });
      }
docs: Sets an enumerable property on `obj` as not `configurable` and not `writable`.
  @function module:sjl.defineEnumProp
  @param obj {Object}
  @param key {String} - Prop name.
  @param value {*}
  @return {void}