Change Torrent.size to long from uint.
Add DownloadTorrent method to the API class.
Add ReleaseType enum. uint changed to ReleaseType

ReleaseType integer values taken from website's advanced search HTML
<select> code.
Add SearchTorrents for various criteria

Add SearchTorrents for various criteria that the advanced search
supports. Also, add Uri.EscapeDataString to the old SearchTorrents.
Add GetArtist by name call.

Also, fix SearchTorrents.
Merge pull request #1 from karamanolev/master

Small fixes and enhancements