Allow the ability to see protected tags as plain text in the regular view of the editor

[Alan Zebchuk]

Allow the addition of tags to be protected so that they're not modified by the editor.

However they should be displayed to the user (just as plain text) when they're in the regular mode without going into the source view to see them.

The idea behind this is to provide tags which are inserted by a custom toolbar plugin, and to have these appear in the editor's regular view, however they need to be protected and shouldn't be changed/removed by the FCKEditor when submitting the data.

[Artur Formella]

This feature is related to Ticket #851