code: function needsSubtitution(prop) {
    var needsSub = false;
    if (typeof prop === 'string') {
      if (prop.indexOf('#{INDEX}') !== -1) needsSub = true;
    } else if (typeof prop === 'object') {
      var str = JSON.stringify(prop);
      if (str.indexOf('#{INDEX}') !== -1) needsSub = true;
    }
    return needsSub;
  }
docs: determines if a property needs substitution
  @returns boolean true if needs substition