Use InChI for Open in Editor if no 3D coordinates

This changes the OpenInEditorHandler to pass the molecule's
InChI formula to avogadro if the molecule has no 3D coordinates.

Change-Id: Idf676e49ad3d415adb92be1bf4ce67b5155d595b
Merge topic 'open-with-inchi' into master

83c1f600 Use InChI for Open in Editor if no 3D coordinates