Replace residue-shift by first residue in the doc
Replace residue-shift by first residue in the doc

Fix an error in the doc.

Fix issue #29

HubLot/PBxplore,pierrepo/PBxplore,jbarnoud/PBxplore,jbarnoud/PBxplore,pierrepo/PBxplore,HubLot/PBxplore