Added InfiltrateToUpgrade

This includes a temporary test example - spies infiltrating vehicles and base defenses to disable them for 30 seconds.
I suggest renaming this to `Includes`.  `fooStance.Includes(Stance.Ally)` is pretty much self-describing.  The `Allied` method below could then be replaced by `fooStance.Includes(Stance.SameOrAlly)` (I don't see why this deserves its own special case)