* Add hassentinelping to governanceinfo
* sentinelping rpc call
* additional fields in mnp
* sentinel ping implementation
* change sentinel state to byte in mnp
* use adjusted time in sentinel ping
* update nTimeLastWatchdogVote if sentinel ping is actual
* remove unused fields
* bump protocol to 70207
* Fix small issues
- fix the error message text in CActivbeMasternodeUpdateSentinelPing;
- add empty string before public: in CActiveMasternode class declaration;
- rename field sentinelPing in CMasternodePing to sentinelIsActual and change $
- decrease sentinelVersion field size to uint16_t;
* revert proto bump for MIN_... consts
* revert changes in getgovernanceinfo
* Update mn vote time for remote masternodes
- call UpdateWatchdogVoteTime in CMasternodeMan::ProcessMessage
- deserialize masternodeping from the previous version archive without exception
- add ability to set time in UpdateWatchdogVoteTime
- set nTimeLastWatchdogVote to masternode ping sigTime if sentinel is actual
- bump CMasternodeMan::SERIALIZATION_VERSION_STRING
* remove mn state checks and add correct rpc param convertion
* fix var names
* Helper class for version in string and integer form
* String version in sentinel ping
Version format is "x.x.x"
* test for bacward compatibility in serialization
* Change VersionInfo class to convert functions
