Bug#737781: want to be able to specify more edge attributes

[Ian Jackson]

Ian Jackson writes ("want to be able to specify more edge attributes"):
> (To be honest, it would be better to have some general way to specify
> arbitrary attributes for the dot output, rather than insisting on
> mapping the dot attribute namespace directly but piecemeal into the
> Graph.pm.  But I haven't implemented that here.)

I have now done this.  I'm going to send the patches (to upstream too)
as followups to this bug.

Thanks,
Ian.