Clickable Icon in the Grid

I am trying to create "Edit" and "Delete" columns in my grid with an appropriate icon for each. I am familiar with ButtonRenderer to get the functionality working, however I can't for the life of me figure out how to screw in an icon into the rendered buttons. 

I found this article, but given it references the Beta grid, I assume that there is a newer solution available. Has anyone found one?

Sorry for the late reply, it's summer vacation period here. To answer your question, no :( It is one of the things I wish there was an add-on for, but I haven't found one yet. Maybe I just have to make one..