* Add ECDSA support
* Add domain separation to ECDSA sighash
* Use InfallibleWrite instead of Write
* Rename funcs
* Fix wrong use if vm.sigCache
* Add TestCalculateSignatureHashECDSA
* Add consts
* Fix comment and test name
* Move consts to the top
* Fix comment
* Replace blue score with DAA score in UTXO entries
* Use DAA score for coinbase maturity
* Use DAA score for sequence lock
* Fix calcBlockSubsidy to use DAA score
* Don't pay to blocks that are not included in the DAA added blocks, and bestow red blocks reward to the merging block
* Fix TestGetPruningPointUTXOs
* Fix TestTransactionAcceptance
* Fix TestChainedTransactions
* Fix TestVirtualDiff
* Fix TestBlockWindow
* Fix TestPruning
* Use NewFromSlice instead of manually creating the hash set
* Add assert
* Add comment
* Remove redundant call to UpdateDAADataAndReturnDifficultyBits
* Add RequiredDifficulty, rename UpdateDAADataAndReturnDifficultyBits to StageDAADataAndReturnRequiredDifficulty and add comments
* Make buildUTXOInvalidHeader get bits as an argument
* Fix comments