support every torrent limit speed, not global limit speed

I agree that enabling users to set max UL\DL speeds for each torrent would be a great feature! Often I am downloading one very large torrent with many seeders, while another torrent with few seeders waits around for bandwidth, sometimes missing its opportunity to download at all.

If I could set the well-seeded torrent to be limited to (for instance) 128KBps while allowing the poorly seeded torrent (for instance) 512KBps download speeds, I could let multiple downloads proceed without pause. The same per-torrent speed prioritization would be useful when uploading as well.