CURRIKI-6056 : PROJECT: Activate Wysiwyg 2.0 instead of TinyMCE

Updated SimpleWikiResource and SimpleHTMLResource.
SimpleHTMLResource loads the wysiwyg editor with xhtml/1.0, while
SimpleWikiResource with xwiki/2.0.
Updated also the text_edit.vm displayer. Removed tinyMCE. Issue fixed on
wysiwyg editor when loading html context for simple html resources.