updated picoTCP to 1.4.0, lowered build optimization levels to -O2, improved selftest

ext/picotcp/test/python/http_server_linux.py

@@ -0,0 +1,13 @@
+#!/usr/bin/python
+from  topology import *
+
+T = Topology()
+net1 = Network(T, "pyt0")
+
+h2 = Host(T, net1, args="httpd")
+
+sleep(1)
+start(T)
+
+wait(h2)
+cleanup()