I think this is what your looking for Jakob:
Did you ever get a solution to this? It sounds like it's simply a missing html file. If anyone has it, could they make it available?
I finally gor MapMarkerEditor “working”. The problem is… it doesn’t work really well. The image dimension seems to be hard coded so no matter what image you upload, it gets squished into a hard coded dimensions. There is also a meaningless “legend” that does nothing and you can’t get rid of. And my main issue is that you have the ability to add custom markers which is exactly what I wanted. but they don’t show up in the tools. There is a toolbar that lets you pick from various shapes and icons, one of them being a marker. You can delete all these shapes from the settings and add custom markers, but no matter what, the same list of custom shapes (and the one default marker) still shows up in the toolbar.