update home page
Add communique 0
add pages.md which contains all wiki pages

Unfortunately, I did not find a way to generate pages.md
automatically. Therefore I use shell command to generate
it manually.

    $ find . -name '*.md' -printf "%f\n" |sed -e s,.md,, |sort \
    |xargs -i echo '* [{}]({}.html)' > pages.md
add link of pages to navbar