feat(deflate): Non working deflate transfer mode

[fclairamb]

[fclairamb]

Ok so I now understand where it's coming from but it requires some design changes. I have created a deflateConn struct that is designed to be used as a net.Conn but the original net.Conn reference is kept in the passive/active transfer handlers.

Which makes us not flush the data at the end of the transfer. This is why download doesn't work.