Add prolog message about documentation with link to the products pages
Use bold markup for prolog message
Set stable version to 4.4 for the moment
First draft of whats-new.txt block
Suggestions from @melissalinkert
Merge pull request #568 from joshmoore/5-doc-fixes

5.x documentation modifications
Merge pull request #567 from sbesson/transition_docs_message

Add prolog message about documentation with link to the products pages