[Bug 522623] Fix 'save all' conflict with Sirius Editor Remove doSave() implementation and fix regression: Since ActivityExplorerEditor became a ISaveablesSource, closing Eclipse with a dirty session does not propose to save changes because ActivityExplorerEditor.isSaveOnCloseNeeded() method return false. Bug: Bug 522623 Change-Id: I177f504d119b122b386aef4d8f0b3e334e9a3652 Signed-off-by: Jeremy Aubry <jaubry@obeo.fr>