Identities

This implements Identities in Bitcore 0.8.
Why not something like...

    var identity = new Identity(“a public key”); // The encoding gets automatically detected.
    var identity = new Identity(“a private key”); // The encoding gets automatically detected.

    identity.getPublicKey(‘base58’);
    identity.getPublicKey(‘compressed’);
    identity.getPublicKey(‘hex’);
    identity.getPublicKey(‘binary’);
    identity.getPublicKeyAsBuffer(‘binary’);