Fixing modal element location

- Don't include the plugin when rendering modal elements.  This allows
  themes to easily override it in their own Elements/admin/modal.ctp.
- Remove the extra 'hide' class as this should go in the aforementioned element
New method CroogoHtmlHelper::thumbnail()

Improves on 8f46ccd. Blindly adding thumbnail classes was not a good idea (tm).
Add more icon mappings
Remove hardcoded ok|remove icons
Reformat Nodes/admin_chooser and adds nowrap css class