Address issue #152 (stupidity prevention in docs)

See issue #152

Add a chunk to the documentation on CSRF protection to help stupid users like me avoid a stupid mistake
Fix bad formatting (markdown in RST)

In my last commit I committed broken formatting (Markdown in an RST document). This commit fixes that.
Merge pull request #155 from hangtwenty/master

Address issue #152 (stupidity prevention in CSRF docs)