Support rank same

[lordnynex]

I think this would require supporting newrank="true" as a valid DiagramOption and support rank="same" on subgraphs.

It might also be nice to support contraint=false as an EdgeOption

[tntobias]

There is the possibility of adding adhoc attributes but I agree explicit options are desirable. I'll commit some changes in coming days to address this.

[li-zhixin]

We are experiencing similar problems and hope that this feature will be supported soon.