unify api (one function for both web and local)

[tfiers]

re :html output here:

• Click node to hide (generate .html page) #66 (comment)_

..we can then also just add :web as a fmt.

(Open=false still applies. Returns the string (which can eg be clipboarded))

[tfiers]

I'd export this function too then I think.

deps?
depgraph
showgraph

I like depgraph. Thanks to Internals namespace, it can coexist with the existing depgraph (edgelist creator)