code: public GitkitUser verifyPassword(String email, String password)
        throws GitkitClientException, GitkitServerException {
        return verifyPassword(email, password, null, null);
    }
docs: Verifies the user entered password at Gitkit server.
  
  @param email The email of the user
  @param password The password inputed by the user
  @return Gitkit user if password is valid.
  @throws GitkitClientException for invalid request
  @throws GitkitServerException for server error