First draft common header + 'add page' button.

Needs a good amount of tweaking. No responsive work yet.
"Add page" button mostly done.
Fix up common & region header + responsive design.
Clean up header bug + uncomment test in base.js
"Add a new LocalWiki region" instead "add region"
Merge branch 'common_header' into hub
Show username on hover for contributors
"Add new page" button means this is now obvious.