add async run

examples/run_async.py

@@ -0,0 +1,20 @@
+from sanic import Sanic
+from sanic.response import json
+from multiprocessing import Event
+from signal import signal, SIGINT
+import asyncio
+
+app = Sanic(__name__)
+
+@app.route("/")
+async def test(request):
+    return json({"answer": "42"})
+
+server = app.create_server(host="0.0.0.0", port=8001)
+loop = asyncio.get_event_loop()
+task = asyncio.ensure_future(server)
+signal(SIGINT, lambda s, f: loop.close())
+try:
+    loop.run_forever()
+except:
+    loop.stop()