message: Change firod default settings to allow mining blocks of up to 2MB.
diff: class CCoinsViewCache;
  /** Default for -blockmaxsize, which controls the maximum size of block the mining code will create **/
  -static const unsigned int DEFAULT_BLOCK_MAX_SIZE = 500000;
  +static const unsigned int DEFAULT_BLOCK_MAX_SIZE = 2000000;
  /** Default for -blockprioritysize, maximum space for zero/low-fee transactions **/
  static const unsigned int DEFAULT_BLOCK_PRIORITY_SIZE = 50000; // 50KB;
  /** Default for -blockmaxweight, which controls the range of block weights the mining code will create **/
  