some quick hack demo (DO NOT MERGE)

@taariq @lkang 

Check out this branch and have a play:
run ``` $ node index.js```

you should see something like this:

```
1. Generate a hd wallet with a seed
2. Generate an address from the hd wallet:
3. Withdraw some Bitcoins to the address that we just generated:  mw43rS7LaXgCYXbjnrk5qgGpSqvYoLWwkg (so that we have some bitcoins to play with)
4. Load up the unspents into wallet
5. Now Send some money to a random address:mkmrA6fjVpneaFyvxbjbZM6w6TASG6zyjQ
6. Success! Now check out the transaction that we just sent from our bitcoin wallet: https://test.helloblock.io/transactions/d59b2393aadf89bdf2d475bee633ba5ff8423dae919d42d32b0ff31b605a9677
```

There is literally nothing simpler than this.