move and check in OpenFlow protocol modules

Move all the protocol code out of the oftest package and into a of10 package to
prepare for supporting more OpenFlow versions.

The generated code is now checked-in to make it simpler to use OFTest.

Backwards compatibility with out of tree tests is maintained by aliasing the
old module names. The basic test module has been changed to use the new API.
diff --git a/src/python/oftest/base_tests.py b/src/python/oftest/base_tests.py
index f91ae60..056f6e9 100644
--- a/src/python/oftest/base_tests.py
+++ b/src/python/oftest/base_tests.py
@@ -11,11 +11,8 @@
 import oftest
 from oftest import config
 import oftest.controller as controller
-import oftest.cstruct as ofp
-import oftest.message as message
 import oftest.dataplane as dataplane
-import oftest.action as action
-
+import of10.message as message
 from oftest.testutils import *
 
 class SimpleProtocol(unittest.TestCase):