Add tracker support for search bar

[zp]

There currently doesn't appear to be anyway to filter torrents by tracker, would be nice if the search bar also checked the tracker list for torrents.

[runbiscuit]

Ah, I see. That's possible :)

For now, I'm looking to optimise the search for torrents first, as there is a noticeable performance issue when I have over 100 torrents running at the same time.

If you can do JS, do feel free to contribute!

[runbiscuit]

Ignore that commit ^
Searching for torrents with a specific tracker will be available when time comes, to be delivered with #12.