Fix invalid XML

[ralexander-phi]

Hey folks, awesome list!

I've also noticed issues with invalid XML in the OPML files. I've gone through each OPML file and manually fixed problems. I stripped extra quotes, converted & to &, stripped out HTML tags, and removed special characters like newlines.

I've validated the output using:

find . -name '*.opml' -print0 | xargs -0 -I '{}' xmllint --valid '{}' --noout 2>&1 | egrep -v "(no DTD)|(opml version)|(    \^)"

This ignores DTD error messages, which aren't technically validation problems.

I've also run the fix-up script in #2, which normalizes a couple minor things.

I've also noticed that many feed URLs are now returning errors. I'm considering replacing or removing those. Is this project interested in third party contributors, or would it be best for me to continue work in a fork?

Thanks for releasing this list!

[ralexander-phi]

The cleanup script made many whitespace fixes, on GitHub you can ignore these by adding w=1 to the URL like: https://github.com/plenaryapp/awesome-rss-feeds/pull/13/files?w=1