In the past, when user open xtls vision on the server side, plain vless+tls can connect.
Pure tls is known to have certain tls in tls characters.
Now server need to specify "xtls-rprx-vision,none" for it be able usable on the same port.
* Add XTLS RPRX's Vision
* Add helpful warning when security is wrong
* Add XTLS padding (draft)
* Fix number of packet to filter
* Xtls padding version 1.0 and unpadding logic