optimize performance for multiple ports

UDPRelay is broken now

tests/gen_multiple_passwd.py

@@ -0,0 +1,19 @@
+#!/usr/bin/python
+
+import os
+import json
+
+with open('server-multi-passwd-performance.json', 'wb') as f:
+    r = {
+        'server': '127.0.0.1',
+        'local_port': 1081,
+        'timeout': 60,
+        'method': 'aes-256-cfb'
+    }
+    ports = {}
+    for i in range(7000, 9000):
+        ports[str(i)] = 'aes_password'
+
+    r['port_password'] = ports
+    print(r)
+    f.write(json.dumps(r, indent=4).encode('utf-8'))