* Clear votes which were created before spork15 activation
* Reject incoming votes which were created pre-DIP3
* Only use voting keys for VOTE_SIGNAL_FUNDING
The other vote signals are meant to be emitted by sentinel and must thus
be signed with the operator key.
* Simplify GetMinVoteTime
* Review suggestions/fixes
* Add missing mutex in CGovernanceObject::RemoveOldVotes
* Make sure gobject collateral was mined
`CGovernanceObject::IsCollateralValid()` would still fail for non-mined collateral later trying to check confirmations
* Fix powLimit for mainnet/testnet
That's a legacy thing, slightly rising it to match the actual bit-shifted value has no effect because real values are already lower.
Also clarify values for all networks in comments.
* Check for script addresses in CSuperblock::ParsePaymentSchedule()
Sentinel should already be downvoting such triggers if they would exist, no need to store/relay them.
* Do not process already known valid vote twice in CGovernanceObject::ProcessVote()
This should be handled by `CGovernanceManager::ProcessVote()` but imo it's better to have this at the `CGovernanceObject::ProcessVote()` level as well.
* Make sure CGovernanceObjectVoteFile::AddVote() never adds/updates already known votes
The way `CGovernanceObjectVoteFile::AddVote()` is used (i.e. wrapped in `CGovernanceObjectVoteFile::HasVote()` condition) it's already the case. Hoever nothing would guarantee consistency if it would be used elsewhere without such wrapper, so it's better to have similar check inside.
* Do not even try mnb recovery when -connect is set
`CConnman::ThreadOpenMasternodeConnections()` thread won't even start when `-connect` is set, so no need to ask for recovery, there is nothing that is going to be able to process such request.
* No need for SIGHASH_ANYONECANPAY in PS collateral signature
Collateral is just a normal tx created and signed by each participant individually, there is no need for special sig types.
* Release semMasternodeOutbound in CConnman::Interrupt()
Re-align Dash code with Bitcoin.
* 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
