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.
> Yes, that would be a better way to implement the checking (Rather than the hacky changing of the ID). Will get to that now.

That'll be great.

> I've made a change that makes the enabling/disabling of wysiwyg for a content type easy to get to, rather than being a hidden (imo) parameter.

Yeah, that's the drawback of using `params` field.  I'll open up a ticket for future considerations.