Disable framing

Set the X-Frame-Options to DENY for added security.
Fixed case for header
Adding brackets.

Too much Coffeescript. Had some filters on. :)
Merge pull request #399 from JetMaddox/master

Disable Framing on all sites.

I'm merging this ***conditionally*** - at some point, we wish to introduce integration with CMSes like WordPress. An easy way to achieve this would be placing NodeBB in an iframe.

At that point in time, we'll want to make this a configurable option via admin panel.