inspector

[Chaoyu Du]

Inspectors would hint the user the duality of FormDiagram and ForceDiagram: edge - edge, node - face, face - node.
Inspectors would work either by user moving the mouse on the object (which might not work perfectly with overlapping objects), or by selecting the object manually.

[Chaoyu Du]

This issue would replace issue #35

[Ricardo Maia Avelino]

I think that to avoid the problem of overlapping, this command should always ask to click.

[Ricardo Maia Avelino]

done