Return the current estimated network hashrate
http://explorer.marketcash.io/api_get/hashrateReturn the current block reward
http://explorer.marketcash.io/api_get/rewardReturn the total available supply
http://explorer.marketcash.io/api_get/supplyReturn the current estimated network difficulty
http://explorer.marketcash.io/api_get/difficultyReturn the last block hash
http://explorer.marketcash.io/api_get/hashReturn the hash address of previous block
http://explorer.marketcash.io/api_get/prev_hash