message: interact: don't use plugin more than once
diff: @@ -45,6 +45,8 @@ function interact (target, options) {
  return interactable;
  }
  +scope._plugins = [];
  +
  /**
  * Use a plugin
  *
  @@ -55,7 +57,12 @@ function interact (target, options) {
  * @return {interact}
  */
  interact.use = function (plugin) {
  + if (scope._plugins.indexOf(plugin) !== -1) {
  + return;
  + }
  +
  plugin.init(scope);
  + scope._plugins.push(plugin);
  return interact;
  };
  