Add ysu.edu and ysubookstore.com

Leaving ysu.edu off by default for now, I think it needs some more
testing. I'm also trying to work with them to fix some of the
mixed-content warnings.

Signed-off-by: Ricky Elrod <ricky@elrod.me>
Merge pull request #548 from CodeBlock/ysu-csis

Add ysu.edu and ysubookstore.com