Experimental HTML to Sketch renderer

We were looking for an easy way to share our style guide between front-end and design teams. `react-sketchapp` by airbnb didn't really work for us (because it requires you to use React, only generic components (no HTML tags) and inline styles), so we build html-sketchapp. Video showing how it works: https://twitter.com/kdzwinel/status/893242605009612801