remove scheme from urls
fixes the following error:
[blocked] The page at 'https://sitepen.github.io/sp-dnd-demo/...' was loaded over HTTPS, but ran insecure content from 'http://downloads.dojotoolkit.org/release-1.7.0/dojo-release-1.7.0/dojo/dojo.js': this content should also be loaded over HTTPS.