Implement UI for autoplacing units on deploy.

If there are unplaced units when a user clicks on the deploy button, they will now see a notification in the deploy summary panel and have the option to autoplace the units at that time.
A minor quibble: this isn't really unplacedUnits, it's an unplacedUnitCount; if I saw this outside of where it was created, I would assume I had access to a list of units or something.