Merge branch 'karlcow-master'

* karlcow-master: (38 commits)
  Remove unused modules - #224
  Issue #224: set the <title> on the client.
  Remove spam comment + doctypes for svg files.
  Fix unclosed span in footer.
  Switch to animate instead of just scrollTop.
  to prevent zoom on iOS
  fixed height label editor fullscreen
  same class
  Test the new "browse issues" sections on the homepage.
  Remove obsolete test.
  Return proper mimetype and response status when an issue is opened/closed. #241.
  Return the correct mimetype and add cache headers for the /comments endpoints. Issue #239 #241.
  Fix posting label changes.
  Add caching headers to the homepage "browse" endpoints.
  Get rid of ensure_xhr decorator (mostly useless, IMO).
  Forward caching headers for /api/issues/number.
  proxy_request should return the Response object, like GitHub-Flask does.
  Forward etag and cache-control (and set proper mime) for /issues/lables.
  Let's switch to if/else.
  Different caches for staging and production.
  ...
proxy_request returns a Response object, need to .json() before .get()
(hi @vladikoff!)
Fix broken link.