proxy format

proxy format 代理格式

Protocol	Example
`http`	`http://proxy-server-over-tcp.com:3128`
`https`	`https://proxy-server-over-tls.com:3129`
`socks(v5)`	`socks://username:password@some-socks-proxy.com:9050` (username & password are optional)
`socks5`	`socks5://username:password@some-socks-proxy.com:9050` (username & password are optional)
`socks5h`	`socks5h://username:password@some-socks-proxy.com:9050` (username & password are optional)
`socks4`	`socks4://some-socks-proxy.com:9050`
`socks4a`	`socks4a://some-socks-proxy.com:9050`