Actually verify the AJAX nonce on form submission
Use a nopriv admin ajax action as well so that subscribers can subscribe
Revert "Use a nopriv admin ajax action as well so that subscribers can subscribe"

This reverts commit 1447b9db212da1597ea4eedbef2c8a33002f4c16.
Merge pull request #14 from washingtonstateuniversity/bug-fix

[PR] Check nonce before submitting form