Yeah, I think if we're not doing any special handling of them we should just lump them all together for now.  As @TomMalbran says, if an extension wants to provide support for a bunch of font type, or video, or whatnot, it can register a new language and take over those file extensions itself.

I'm not sure why we even break out audio separately -- but just in case extensions are relying on it, I'd like to leave it as-is for now.

@SAPlayer The reason .tiff isn't listed under images is because Brackets doesn't support it -- our image-preview UI can't render it, and it's not a format used when coding CSS/HTML (for the same reason).