tinymce styles fixed in upload/links modal

- autotoc: add example to render tabs + automatically disable scrolling if pattern elements has "autotabs" class
- add separated template for image upload, use autotoc to get tabs from fieldsets, improve styles
- tinymce uses autotoc so make sure pattern.tinymce.less includes pattern.autotoc.less
Merge pull request #295 from plone/simahawk-tinymce-modal-improvements

Improve tinymce links/images modals + improved autotoc docs