Check aiohttp version

gns3server/web/web_server.py

@@ -43,6 +43,9 @@ import gns3server.handlers
 import logging
 log = logging.getLogger(__name__)
 
+if not aiohttp.__version__.startswith("1.3"):
+    raise RuntimeError("You need aiohttp 13 for running GNS3")
+
 
 class WebServer: