Hooks into multiple events of a scanner.

def observe_scanner(self, scanner):
        """
        Hooks into multiple events of a scanner.
        """
        scanner.observe(scanner.ALL_EVENTS,
                        self.absorb_args(self.modules.restore))
        if self.clear:
            scanner.observe(scanner.ALL_EVENTS,
                            self.absorb_args(self.clear_on_run))
        scanner.observe(scanner.ALL_EVENTS, self.absorb_args(self._run))
        if self.debug:
            scanner.observe('created',  echo("callback - created  %(file)s"))
            scanner.observe('modified', echo("callback - changed  %(file)s"))
            scanner.observe('deleted',  echo("callback - deleted  %(file)s"))
        self._scanners.append(scanner)