Added read-only tinyMCE when noedit is true

When a html field with wysiwyg was set to noedit, we only saw the html code (not rendered). It was very easy to fix because TinyMCE already comes with a read-only option.

Secondly, I removed ui-wysiwyg-dev.js, I made a simple search and figured it was unused, it seems to be a forgotten idea. @JedWatson Tell me if I'm wrong about this and I will update this PR.