message: [BUG] Remove ambiguous call to distance in ParseAccChecksum
diff: uint32_t ParseAccChecksum(uint256 nCheckpoint, const libzerocoin::CoinDenomination denom)
  {
  - int pos = distance(libzerocoin::zerocoinDenomList.begin(),
  + int pos = std::distance(libzerocoin::zerocoinDenomList.begin(),
  find(libzerocoin::zerocoinDenomList.begin(), libzerocoin::zerocoinDenomList.end(), denom));
  nCheckpoint = nCheckpoint >> (32*((libzerocoin::zerocoinDenomList.size() - 1) - pos));
  return nCheckpoint.Get32();
  