Master type failover

Enables the master to only accept a limited amount of minions. If a minion connects that is already connected, it is allowed, else its denied by sending it the string 'full'.

Enables the minion to connect to a single master from a list of masters (not all masters like in multimaster mode). If it is denied by a master because the master has maxed out its minions, it acts on the returned string 'full'  and tries the next master in the list until it is accepted by one (caching the minions key counts as accepted) or all masters have rejected the connection. If no master accepts it, the minion exits.