New returns a ready-to-go miner that is not mining.

BlockMemory is the maximum number of blocks the miner will store Blocks take up to 2 megabytes of memory, which is why this number is limited.

HeaderMemory is the number of previous calls to 'header' that are remembered.

MaxSourceBlockAge is the maximum amount of time that is allowed to elapse between generating source blocks.

Miner struct contains all variables the miner needs in order to create and submit blocks.