message: Update block to JSON method
diff: @@ -218,6 +218,14 @@ UniValue blockToJSON(const CBlock& block, const CBlockIndex* blockindex, bool tx
  CBlockIndex *pnext = chainActive.Next(blockindex);
  if (pnext)
  result.push_back(Pair("nextblockhash", pnext->GetBlockHash().GetHex()));
  +
  + result.push_back(Pair("flags", strprintf("%s%s", blockindex->IsProofOfStake()? "proof-of-stake" : "proof-of-work")));
  + result.push_back(Pair("proofhash", blockindex->hashProof.GetHex()));
  + result.push_back(Pair("modifier", blockindex->nStakeModifier.GetHex()));
  +
  + if (block.IsProofOfStake())
  + result.push_back(Pair("signature", HexStr(block.vchBlockSig.begin(), block.vchBlockSig.end())));
  +
  return result;
  }
  