getReadableHashrateString

[CerveloFellow]

On my admin userlist page, the readable hashrate was showing all of the array indices with the existing algorithm. So for example 1.24 KH/s would display as 1.24 h/s Kh/s Mh/s Gh/s Th/s Ph/s

I changed the function in api.js to this and got better results.

I'm not real familiar with git, otherwise I would have done a pull request with these changes.

function getReadableHashRateString(hashrate){
var displayrate = ["", "k", "M", "G", "T", "P"];
if(hashRate == 0) return '0 ';
var k = 1024,
i = Math.floor(Math.log(hashRate) / Math.log(k));
return parseFloat((hashRate/ Math.pow(k, i)).toFixed(2)) + ' ' + displayrate[i];
}