Simple way to prevent certain content types from using a wysiwyg editor

This allows an administrator to disable the wysiwyg editor on select content types by adding a no_wysiwyg=true param to the content type.

This is needed because CKEditor sometimes thinks it's better than the person writing the content and rewrites the HTML.
> Thinking about it, I think the ideal would actually be to make it a field in the types table?

I prefer not to in this case.

I think, instead we should modify the wysiwyg js setup code to skip initializing for DOM elements with certain class or attribute.