Error handler for 406.
Added issue number and title to issue page title tag
Merge branch 'issue-views' of github.com:tagawa/webcompat.com into tagawa-issue-views

* 'issue-views' of github.com:tagawa/webcompat.com:
  Added issue number and title to issue page title tag
  Error handler for 406.
Merge branch 'tagawa-issue-views' into dev.webcompat.com

* tagawa-issue-views:
  Added issue number and title to issue page title tag
  Error handler for 406.