bitpay/bitcore — pull request #280 by ryanxcharles (2014-04-22 20:56:12+00:00)
Title: BIP32 speed improvement

* remove multiple concats with one, more efficient, concat
* allow generating blank BIP32 for internal use
* other minor improvements

Speed test:
```
var d1 = new Date();
for (var i = 0; i <= 10000; i++) {
var bip32 = new bitcore.BIP32();
var bip32b = bip32.derive('m/5');
console.log(i);
}
var d2 = new Date();
console.log(d2-d1);
```

This code took 32 seconds on master, and 20 seconds on this new branch on my machine. So things are about 30% faster.