GWT: x.x, Portal Corpus Edition CMS pages

See:
https://groupes.renater.fr/wiki/txm-info/public/specs_doc_corpus

First step implements :

• CMS pages and hyperlinks
• command to open a “page” = page (MD)
• command to open “introduction” of a corpus = documentation
• (the outline is an html page inserted (as iframe?) into each page of the introduction)

Second step implements :

• current page path line
• outline view

(from redmine: issue id 1087, created on 2014/10/22 by Alexey Lavrentev)

• Relations:
  • relates #595
  • child #1086
  • child #597 (closed)
  • child #667
  • child #1125 (closed)