message: change default AD higher to make it costly for a minority hash power to exceed it
diff: enum {
  TYPICAL_BLOCK_SIZE = 200000, // used for initial buffer size
  DEFAULT_MAX_GENERATED_BLOCK_SIZE = 1000000, // default for the maximum size of mined blocks
  - DEFAULT_EXCESSIVE_ACCEPT_DEPTH = 4,
  + DEFAULT_EXCESSIVE_ACCEPT_DEPTH = 12, // Default is 12 to make it very expensive for a minority hash power to get lucky, and potentially drive a block that the rest of the network sees as "excessive" onto the blockchain.
  DEFAULT_EXCESSIVE_BLOCK_SIZE = 16000000,
  DEFAULT_MAX_MESSAGE_SIZE_MULTIPLIER = 16, // Allowed messages lengths will be this * the excessive block size
  MAX_COINBASE_SCRIPTSIG_SIZE = 100,
  