Use Symphony::isLoggedIn(); in order to check if user is logged in. Fixes #22
Better HTTP get detection

Just checking if the $_POST array is empty is not enough. If you use verbs like PUT or DELETE, you do not want anything to be cached, since those operation would change the render. This change introduce a private function that will contain the logic regarding if the request is a GET (or HEAD) or not and the function is called both in intercept and in write.
Exclusions: treat 'page/*' is the same as 'page*'

This bug as long been present and I must tell that it make creating exclusions a bit harsh.
Fixes #9.
Added COLLATE=utf8_unicode_ci for new installs

Fixes #20. I did not wanted to update existing install because I fear we may invalidate all the cached entries.