1.5.0

• Make StreamException constructors public
• Add ability to use SDK with multiple clients. Now we can pass custom client implementation to every
  request object.

    var client = new DefaultClient();
    var response = App.get().withClient(client).request();

• Add App.verifyWebhookSignature
• Add User.create_token(String apiSecret, String userId, Date expiresAt, Date issuedAt)