Deprecations

• exc.verifier is deprecated in favor of qq.verifier.

Features

• qq.need_verify is added to check if verification is needed.
  If True, qq.verifier.fetch_image() and qq.verifier.verify(code) is available.

• fix: verify code
• fix: qzone feed

Breaking changes

• exc.verifier.image is replaced with exc.verifier.fetch_image().
  By calling exc.verifier.fetch_image() repeatedly, new verify codes will be received.