Set complete flag for this comic, ie. all comics are downloaded.

def setComplete(self, basepath):
        """Set complete flag for this comic, ie. all comics are downloaded."""
        if self.endOfLife:
            filename = self.getCompleteFile(basepath)
            if not os.path.exists(filename):
                with open(filename, 'w') as f:
                    f.write('All comics should be downloaded here.')