added speed limit support for qBittorrent
added speed limit support for qBittorrent

1. maxupspeed: support to set torrent upload speed limit. Unit in KiB/s  --same as transmission
2. maxdownspeed: support to set torrent download speed limit. Unit in KiB/s --same as transmission
malkavi/Flexget,Flexget/Flexget,Flexget/Flexget,Flexget/Flexget,malkavi/Flexget,Danfocus/Flexget,JorisDeRieck/Flexget,Danfocus/Flexget,Danfocus/Flexget,malkavi/Flexget,crawln45/Flexget,tobinjt/Flexget,crawln45/Flexget,tobinjt/Flexget,Danfocus/Flexget,ianstalk/Flexget,crawln45/Flexget,JorisDeRieck/Flexget,JorisDeRieck/Flexget,ianstalk/Flexget,ianstalk/Flexget,gazpachoking/Flexget,malkavi/Flexget,Flexget/Flexget,crawln45/Flexget,JorisDeRieck/Flexget,gazpachoking/Flexget,tobinjt/Flexget,tobinjt/Flexget