Windows support (freezing).

Client notification support.
Hypervisor manager changes.
IOU reload support.
Switch to non-dynamic module loading because of a multiprocessing
problem on Windows.

gns3server/main.py

@@ -18,6 +18,7 @@
 
 import datetime
 import sys
+import multiprocessing
 import logging
 import tornado.options
 import gns3server
@@ -34,6 +35,10 @@ def main():
     Entry point for GNS3 server
     """
 
+    if sys.platform.startswith("win"):
+        # necessary on Windows to use freezing software
+        multiprocessing.freeze_support()
+
     current_year = datetime.date.today().year
     print("GNS3 server version {}".format(gns3server.__version__))
     print("Copyright (c) 2007-{} GNS3 Technologies Inc.".format(current_year))