Add render to changeOptions

That is something that I always add to my local version of ReactBackbone and thought that it could very well be part of the official repo.

Sometimes, you just want to trigger a rerender of a ReactBackbone component without triggering a `change` event (i.e. if your model is listening to `change` and you absolutely don’t that action to be fired). Other times you may want to `Model#set` with  `silent: true` and render the changes later for performance sake.

Also useful for collections that don’t have a `change` event per se.