Disclaimer: Please follow this guide being aware of the fact that I'm not an expert regarding the things outlined below, however I made my best attempt. A few people in IRC confirmed it worked for them and the results looked acceptable.
Attention: After following all the steps run gdk-pixbuf-query-loaders --update-cache as root, this prevents various gdk-related bugs that have been reported in the last few hours. Symptoms are varied, and for Cinnamon the DE fails to start entirely while for XFCE the icon theme seemingly can't be changed anymore etc.
Check the gist's comments for any further tips and instructions, especially if you are running into problems!
Results after following the guide as of 11.01.2017 13:08: