Coding style.

- asyncio.async -> asyncio.ensure_future

vigil/__main__.py

@@ -570,7 +570,8 @@ class Screen:
             future = worker_.job_runner(
                 self._summary, self._log, self._summary._jobs_added_event,
                 self._appearance_changed_event)
-            worker_.future = asyncio.async(future, loop=self._main_loop)
+            worker_.future = asyncio.ensure_future(future,
+                                                   loop=self._main_loop)
         self.workers = workers
 
     def stop_workers(self):

vigil/fill3.py

@@ -464,7 +464,8 @@ def main(loop, appearance_changed_event, screen_widget, exit_loop=None):
     loop.add_signal_handler(signal.SIGWINCH, appearance_changed_event.set)
     loop.add_signal_handler(signal.SIGINT, exit_loop)
     loop.add_signal_handler(signal.SIGTERM, exit_loop)
-    asyncio.async(_update_screen(screen_widget, appearance_changed_event))
+    asyncio.ensure_future(
+        _update_screen(screen_widget, appearance_changed_event))
     with terminal.hidden_cursor(), terminal.fullscreen(), \
             _urwid_screen() as urwid_screen:
         loop.add_reader(sys.stdin, on_input, urwid_screen, screen_widget)