Creates the top level directory.

def build(self, *args, **kwargs):
        """Creates the top level directory."""
        # Create the directories of the work.
        self.indir.makedirs()
        self.outdir.makedirs()
        self.tmpdir.makedirs()

        # Build dirs and files of each task.
        for task in self:
            task.build(*args, **kwargs)

        # Connect signals within the work.
        self.connect_signals()