On paste: Do not handle multiple newline separated torrent ids
On paste: Do not handle multiple newline separated torrent ids

If the user accidentally pastes something that's not a torrent id, then
they get one "Invalid torrent Id" error for each line of the text.

Sure, this removes a "feature", but it's a pretty surprising one. When
I added it, I was being too clever, IMO.

The trim code can be removed, because that's handled in
controllers.torrentList.addTorrent().

feross/webtorrent-app,feross/webtorrent-desktop,michaelgeorgeattard/webtorrent-desktop,feross/webtorrent-desktop,feross/webtorrent-app,feross/webtorrent-app,feross/webtorrent-desktop,webtorrent/webtorrent-desktop,michaelgeorgeattard/webtorrent-desktop,webtorrent/webtorrent-desktop,michaelgeorgeattard/webtorrent-desktop,webtorrent/webtorrent-desktop