Show un-estimated stories in Live Plan timeline (through default estimate or option to always show)

As a user, I would like to see stories in the Live Plan timeline, regardless of whether they have been formally estimated, so I can have a plan going forward.

A couple of ways to accomplish this:

1. Put a toggle in the configuration screen to show un-estimated stories in the timeline view
2. Add an option for Default Estimate in the configuration screen that un-estimated stories can use. This is in place in the standard plans today
3. Put a filter in the Review and commit changes dialog to easily filter out changes to Story Points