fix https://github.com/xtaci/kcp-go/issues/273

added Control() function to give user privilege to set net.PacketConn

fix recycle

fix for issue: https://github.com/xtaci/kcp-go/issues/259

Bump gopkg.in/yaml.v3 from 3.0.0-20200313102051-9f266ea9e77c to 3.0.0…

upd deps

optimize left edge finding in autotune

* Git ignore go vendor folder

* Update go dependencies

fix race and parityshard leaks