Pull #78 followup: fixing erroneous replacement of a for..in by a for..of
Merge pull request #79 from Yoric/yoric

Pull #78 followup: fixing erroneous replacement of a for..in by a for..of
Issue #80: Graphics for the Vortex
Issue #80 Centering the vortex
Issue #80 Removing immortality :)
Merge pull request #81 from Yoric/yoric

Making the vertex look like a vertex
Issue #56: replace the Set object by an array
Remove the unused health div in the index.html