Merge pull request #2 from brotchie/master

Added dogecoind error code as a property on the Error instance when an error occurs
Merge pull request #3 from brotchie/master

Added passphrase callback to assist temporary wallet unlocks.
3rd party examples
Update README.md
Update README.md
Update README.md
Update README.md
Update LICENSE
Fixed bug where if result is integer and zero an object is returned.

This bug manifested when you called `getBalance` and the resulting
balance was zero. Instead of a return value of zero, you would get
the response JSON object. This is because

    fn(null, data.result || data)

will ignore data.result if data.result === 0.