add a simple pytho echo client

test/compatibility/python/websockets/echo_client.py

@@ -0,0 +1,25 @@
+#!/usr/bin/env python3
+
+# websocket send client
+
+import argparse
+import asyncio
+import websockets
+
+
+async def send(url):
+    async with websockets.connect(url) as ws:
+        while True:
+            message = input('> ')
+            print('Sending message...')
+            await ws.send(message)
+            print('Message sent.')
+
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser(description='websocket proxy.')
+    parser.add_argument('--url', help='Remote websocket url',
+                        default='wss://echo.websocket.org')
+    args = parser.parse_args()
+
+    asyncio.get_event_loop().run_until_complete(send(args.url))