Forbidd access to all Theme .blade.php files via .htaccess

This closes a critical security breach.
Without that somebody could go to `example.com/themes/theme_name/post.blade.php` and see it' s complete content in plain text.
Merge pull request #37 from ChristianGaertner/patch-2

Forbidd access to all Theme .blade.php files via .htaccess