Make sure we can have > 1 fading out leave behind items

A user could swipe a conversation away, and then just keep swiping
We need to make sure that as they do that, we have the old
fading leave behind items keep fading out and just add new ones to the list.

Removes a few unnecessary styles.

Makes sure we don't restart animations on fading leave behinds.
Change-Id: I8927339a9c4d78304b98f2322fdd7c5dab484cdb
3 files changed