Multiline text

I'd like to be able to add multi-line text to vertices and edges when drawing a graph. Naively adding \n to the text doesn't render correctly (renders a box in place of the newline).

I've found that this feature was already requested on the mailing list in 2013, but couldn't find any followup. Apparently the text is currently rendered using cairos show_text function in src/graph/draw/graph_cairo_draw.cc. Apparently that function is not intended for serious use by applications. It is apparently recommended to use pango instead.