Added the ability to create a new master bip32 with new private key and chain code. The way this works is like this:
var bip32 = new BIP32('mainnet');
or:
var bip32 = new BIP32('testnet');
This BIP 32, or HD wallet implementation is directly copied from this repo:
https://github.com/sarchar/brainwallet.github.com/tree/bip32
It does not actually work with this commit, since it is designed to work with
bitcoin-js in the browser. It needs to be modified to work with bitcore in node
and the browser.