Graph input-output demo, some documentation.

Doc review+corrections in my own documentation according to the reviewers comments.

Mainly doc review.

Uh, long comment arrives... Zoom update does not happen after editorial steps. Nodes initial color is light blue, if there is any item under them. Strange node-text relations disappeared. Initial values of new items are given now in a more common way. The wood-cutter way of handling default values of properties is now changed.

Function names are corrected according to naming conventions.

Hmmm...