fixes #17535, warn of cross-domain failure when loading css via dojox/html/styles

Squashed commit of the following:

commit 78c74e046bbfe52383114dcffdea7cc9931e63c9
Author: Wouter Hager <wshager@gmail.com>
Date:   Wed Apr 30 00:50:36 2014 +0200

    added warning

commit f2dca7b091f70ef3819c312ade1dd0c752e21372
Author: whager <whager@benjamins.nl>
Date:   Sun Apr 27 11:19:42 2014 +0200

    fixes cssRules property read fail due to same-origin policy