Fix closing and restoring editors in presence of temporary editors.
* Editor manager should abort closing core, if there's a ICoreListener that aborts closing of a editor. * Don't save state of temporary editors, and don't save them as open in a splitter. So restoring the editor manager state won't try to reopen temporary editors. Task-number: QTCREATORBUG-2845 Task-number: QTCREATORBUG-2841 Reviewed-by: Tobias Hunger