[Feat] Continue downloading from last downloaded file state

[tdlbugreport]

Proposal

if you downloaded 500mb from 1GB file (then connection drop happens or manual cancellation happens, etc) it should continue from already downloaded 500mb point of temp file.

Background

it's quite frustrating to download from start when you tries to download huge files on QoS'd state..

Workarounds

no. tdl always downloads file from the start on new session.