[android] #UX Automatically expand multiple file torrent transfer when adding file from same torrent

[gubatron]

When an user downloads a partial torrent file from a torrent, then goes back to search results and adds another partial file from the same torrent, it's not obvious to the users that the file belongs to the same torrent and they think the old file is being downloaded again.

To avoid such confusion, we should probably auto-expand the transfer and highlight the file that's been added to the transfers screen.

This logic would most likely take place on TransfersFragment

[gubatron]

CC: @votaguz @alejandroarturom @X-NicON @dennistobar (@arubinofaux wanna do some android?)

$15 bounty for merged pull request to be paid in Bitcoin at the exchange rate of the day on Bitven.com