Destroy the environment.

        Does the following:

        1. calls :py:meth:`~creamas.core.Environment.save_info`
        2. for each agent: calls :py:meth:`close`
        3. Shuts down its RPC-service.

def destroy(self, folder=None, as_coro=False):
        '''Destroy the environment.

        Does the following:

        1. calls :py:meth:`~creamas.core.Environment.save_info`
        2. for each agent: calls :py:meth:`close`
        3. Shuts down its RPC-service.
        '''
        async def _destroy(folder):
            ret = self.save_info(folder)
            for a in self.get_agents(addr=False):
                a.close(folder=folder)
            await self.shutdown(as_coro=True)
            return ret

        return run_or_coro(_destroy(folder), as_coro)