[Enhanced] Multi-threaded download support

[5bc2e7]

Now it can only download single-threaded, the maximum download speed is about 50Mbps( I use the IDM downloader ), my network is 500Mbps.

It would be nice if we could support multi-threaded downloads.

Great project, thanks for your work! Respect!

[5bc2e7]

This project supports multithreaded downloads: https://github.com/iyear/tdl

[EverythingSuckz]

@5bc2e7 I'll definitely look into it, Thank you for your suggestion.