Add getBalanceHistory(batch)

[Darkster1]

Hello,

Please add a feature that gets the address balance including the tx history, as it's quit intensive to fetch an addresses history and calculate the total received/total seend values it requires calls to getBalanceBatch, getHitoryBatch and TransactionBatch (txBatch requests are needed for each tx from getTransactionBatch) plus addresses need conversion to a scripthash that needs to be compared to an address and the bitcoinjs library needs to convert the address to an output script too that's quit a lot of code. Would be nice if some electrum client supports just it be design.