Comment out unused MAX_BLOCK_SERIALIZED_SIZE
Comment out unused MAX_BLOCK_SERIALIZED_SIZE

Goldcoin does not use Serialized Blocks. Updated BITCOIN to GOLDCOIN in three places.
goldcoin/goldcoin,goldcoin/goldcoin,goldcoin/goldcoin,goldcoin/goldcoin,goldcoin/goldcoin,goldcoin/goldcoin