Choose first unused color for added team (addresses
issue #431) + other small changes
let animation objects delete themselves after they are not being used anymore
PS:
I don't like that we create new animation objects every single time before a page transition is done, I'm sure that can be done in a nicer way.
But at least we're not keeping those non-reused objects around forever now...
Workaround for visual bug.
issue #442