new-list-entry: Add some margin-bottom

This unifies its look with the StartConversationEntry's
Tweet: Save the inline media's original web url
filter-list-entry: Set the content label'x xalign to 0

Keeps ellipsizing labels from jumping
HomeTimeline: Don't wrongly favorite the user's tweets

We don't only get favorite events when the authenticating user favorites
something, but also when other users favorite a tweet of the
authenticating user, so just check for the source of the event.