Coding style.

- Tidy up task properly. Was getting a warning on shutdown.

eris/__main__.py

@@ -1139,11 +1139,14 @@ def main(root_path, loop, worker_count=None, editor_command=None, theme=None,
         for worker in screen.workers:
             loop.create_task(worker.future)
         if sys.stdout.isatty():
-            loop.create_task(
+            update_task = loop.create_task(
                 fill3.update_screen(screen, appearance_changed_event))
-            with fill3.context(loop, appearance_changed_event, screen,
-                               exit_loop=exit_loop):
-                loop.run_forever()
+            try:
+                with fill3.context(loop, appearance_changed_event, screen,
+                                   exit_loop=exit_loop):
+                    loop.run_forever()
+            finally:
+                update_task.cancel()
             log.log_message("Program stopped.")
         else:
             try:

eris/fill3.py

@@ -535,9 +535,13 @@ def _main():
     loop = asyncio.get_event_loop()
     appearance_changed_event = asyncio.Event()
     screen = _Screen(appearance_changed_event)
-    loop.create_task(update_screen(screen, appearance_changed_event))
-    with context(loop, appearance_changed_event, screen):
-        loop.run_forever()
+    update_task = loop.create_task(
+        update_screen(screen, appearance_changed_event))
+    try:
+        with context(loop, appearance_changed_event, screen):
+            loop.run_forever()
+    finally:
+        update_task.cancel()
 
 
 if __name__ == "__main__":