Fixes #1208 xmlhttp.php theme loading doesn't make any sense
Merge remote-tracking branch 'upstream/feature' into fix-1208
Added check for cookied theme, whether no theme was loaded and the CDN check.
Also moved a wrong comment in global.php
Merge pull request #1209 from JN-Jones/fix-1208

Fixes #1208 xmlhttp.php theme loading doesn't make any sense