fix slow connection, '/' in pub key, and hbbr wait for key, and possible

solution for https://github.com/rustdesk/rustdesk-server/issues/24

src/main.rs

@@ -21,6 +21,7 @@ fn main() -> ResultType<()> {
         -u, --software-url=[URL] 'Sets download url of RustDesk software of newest version'
         -r, --relay-servers=[HOST] 'Sets the default relay servers, seperated by colon'
         -M, --rmem=[NUMBER(default={})] 'Sets UDP recv buffer size, set system rmem_max first, e.g., sudo sysctl -w net.core.rmem_max=52428800. vi /etc/sysctl.conf, net.core.rmem_max=52428800, sudo sysctl –p'
+        , --mask=[MASK] 'Determine if the connection comes from LAN, e.g. 192.168.0.0/16'
         -k, --key=[KEY] 'Only allow the client with the same key'",
         RENDEZVOUS_PORT,
         RMEM,