Fix ngClass animation bugs with enter, move and leave

[matsko]

No description provided.

[IgorMinar]

reposting as PR comment so that it doesn't get lost when a forced push happens:

it feels wrong to be $eval-ing expressions outside of the digest loop because that suggests that you can change the model here, which is wrong.

I think that this post digest queue is so different from the original $evalAsync queue that we shouldn't even reuse the $evalAsync method for this, but rather create a new method on scope for queueing up this work.

I would go as far as creating $$postDigest method that allows pushing stuff into this queue and then the rootScope would flush that after digest. This unblocks us without forcing us to expose a public api that we want to commit to.

I think that we can do way better than this, but given that we don't want to delay 1.2 we should just create this "experimental" api and call it done for now.