gexf12: fix omitable and unbounded attributes (!619) · Merge requests · gonum / gonum · GitLab

Sebastien Binet requested to merge fixes/gexf into master Oct 11, 2018

Created by: kortschak

Even with mechanical help I can get XML wrong.

Fix xml: tag to omitempty for Attribute.
Fix pointer type for omitable fields in Graph.
Make Attributes in Graph a []Attribute to match the xsd and the rnc.

Please take a look.