* Store masternodes in a map instead of a vector, drop unused functions in CMasternodeMan
* CTxIn vin -> COutPoint outpoint
* do not use CMasternodeMan::Find outside of the class
* update GetMasternodeInfo
* safe version of GetNextMasternodeInQueueForPayment
* fix ProcessMasternodeConnections
* bump CMasternodeMan::SERIALIZATION_VERSION_STRING