added full udhcp integration

examples/udhcp/sample.script

@@ -0,0 +1,7 @@
+#!/bin/sh
+# Currently, we only dispatch according to command.  However, a more
+# elaborate system might dispatch by command and interface or do some
+# common initialization first, especially if more dhcp event notifications
+# are added.
+
+exec /usr/share/udhcpc/sample.$1