NZonscreen support

[bohwaz]

Before submitting a pull request make sure you have:

• [X] At least skimmed through adding new extractor tutorial and youtube-dl coding conventions sections
• [X] Searched the bugtracker for similar pull requests

In order to be accepted and merged into youtube-dl each piece of code must be in public domain or released under Unlicense. Check one of the following options:

• [X] I am the original author of this code and I am willing to release it under Unlicense
• [ ] I am not the original author of this code but it is in public domain or released under Unlicense (provide reliable evidence)

What is the purpose of your pull request?

• [ ] Bug fix
• [ ] Improvement
• [X] New extractor
• [ ] New feature

---

Description of your pull request and other information

Add support for https://www.nzonscreen.com/

[dstftw]

Read

adding new extractor tutorial and youtube-dl coding conventions sections

and fix all issues.

[bohwaz]

Hey, I switched from playlist to multi_video, if that's what you implied.

But I did use the extractor tutorial, so if there is still something wrong, can you please mention any specific issue you think my code has? Thanks.