Feature Request: Auto-center on `selectedDate`

First off, love the `CalendarStrip` component. I may ultimately fork it to add functionality and then check back in if I'm able to do these myself. Here's the request -- if it's possible with the current props, though, let me know!

Scenario:

As a user, I want to select a date and have the strip automatically center that date. Until I select another date, the currently selected date should stay centered. UX-wise, this means dates would scroll behind the centered date until a new date is selected; once selected, the new `selectedDate` would automatically center.