* Multi-quorum InstantSend, complete refactoring
+ cleanup for IS and partial protobump
* more changes:
- allow InstantSend tx to have 10 inputs max
- store many unique tx hashes in mapVotedOutpoints
- more checks in AcceptToMemoryPoolWorker (moved from ProcessMessage + CTxLockRequest(tx).IsValid() )
* More changes:
- let multiple lock candidates compete for votes
- fail to vote on the same outpoint twice early
* More changes:
- notify CInstantSend on UpdatedBlockTip -> remove cs_main from CheckAndRemove()
- notify CInstantSend on SyncTransaction -> count expiration block starting from the block corresponding tx was confirmed instead of the block lock candidate/vote was created
- fixed few locks
* add comments about nConfirmedHeight
* Fix "Block vs Lock" edge case
* Fix "Block vs Lock" edge case, p2
* Fix issues:
- fix logic for locking inputs and notifying - see UpdateLockedTransaction, TryToFinalizeLockCandidate
- add missing hash inserting in ProcessTxLockVote
- add nMaxBlocks param to ResolveConflicts to limit max depth allowed to disconnect blocks recursively
- fix false positive mempool conflict
- add missing mutex locks
- fix fRequireUnspent logic in CTxLockRequest::IsValid
