Rotate graphs to vertical orientation

[nowthis]

Allow top-to-bottom or bottom-to-top flow diagrams.

Part of this is a simple coordinate transform.

The hard part will be the placement of labels; simply rotating those won't look good.

[mmoole]

Maybe another Idea would be to just rotate the labels - then one could rotate the whole diagram like one wants to afterwards when having it inserted in the program where it is used. This would be extremely useful for use cases if you want to visualize a flow from top to bottom for example.