Added #169 CONTROLMASTER option

sync.conf.example

@@ -70,6 +70,9 @@ SSH_COMPRESSION=true
 ## Ignore ssh known hosts. DANGER WILL ROBINSON DANGER ! This can lead to security issues. Only enable this if you know what you're doing.
 SSH_IGNORE_KNOWN_HOSTS=false
 
+## Use a single TCP connection for all SSH calls. Will make remote sync faster, but may work less good on lossy links.
+SSH_CONTROLMASTER=false
+
 ## Check for connectivity to remote host before launching remote sync task. Be sure the hosts responds to ping. Failing to ping will stop sync.
 REMOTE_HOST_PING=false