Coursera-dl

Features:
- Do not expand class names if there is a specialization with the same name,
but add --specialization flag to do that explicitly (673)

Bugfixes:
- Switch to newer API for syllabus and lecture retrieval (665, 673, 634)

Features:
- You can now download specializations: the child courses will be
downloaded automatically

Bugfixes:
- Use TLS v1.2 instead of v1.0
- Switched to api.coursera.org subdomain for subtitles requests (664)

Bugfixes:
- Specify utf-8 encoding in setup.py to fix installation on Windows (662)

Features:
- Add support for "peer assignment" section (650)

Bugfixes:
- Switched to api.coursera.org subdomain for API requests (660)

Features:
- Support Coursera Notebooks (option: `--download-notebooks`)
- Add hints in the documentation for users in China