Remove filter on various URIs to avoid CORS issues

We were trying to use the same domain - wp.wsu.edu on everything,
rather than having a content URL for each individual site. That's
pretty ridiculous and could cause other, unknown issues down the
road. Right now it's causing an issue with a CORS request for some
font awesome icons.
Don't specify a WP_CONTENT_URL
Merge pull request #154 from washingtonstateuniversity/bug/cors-153

[PR] Stop modifying WP_CONTENT_URL with root domain