Summary

Add another map method taking self instead of &self.

Motivation

This helps when the node weight or edge weight is some data structure that needs to be moved to another graph.

Details

• What code needs to change? New traits? Which modules?

Add a new method (map_owned?) to Graph and StableGraph.

• Is this a new graph algorithm? Include links to papers, Wikipedia, or other
  implementations of this algorithm that exist.

No.

• Are you willing to implement this yourself? Mentor someone else and help them
  implement it?

I can implement it myself. Any suggestions on the method name?