Crystax support for Feedparser

[kuzeyron]

Added python3crystax to the list.

[AndreMiras]

Thanks for the pull request.
The commit title is not meaningful enough. Commit body can explain why this is needed, what error it solves

[AndreMiras]

Closing in favor of #1324
Please note that you should normally just amend your commit rather than creating a new pull request each time you need to make a little change.

[kuzeyron]

@AndreMiras I couldn't find the place to change on the old one. So if I would be you, do the changes instead of having this odd game.

[AndreMiras]

I cannot do the changes myself to your PR unless you explicitly give access to it.
Reading this article could help you https://medium.com/@igor_marques/git-basics-adding-more-changes-to-your-last-commit-1629344cb9a8
It's very useful trick, give it a try, it's easy once you know it.