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/__init__.py b/src/python/oftest/__init__.py
index 3974e08..65a5648 100644
--- a/src/python/oftest/__init__.py
+++ b/src/python/oftest/__init__.py
@@ -1,4 +1,5 @@
 '''Docstring to silence pylint; ignores --ignore option for __init__.py'''
+import sys
 
 # Global config dictionary
 # Populated by oft.
@@ -7,3 +8,9 @@
 # Global DataPlane instance used by all tests.
 # Populated by oft.
 dataplane_instance = None
+
+# Alias of10 modules into oftest namespace for backwards compatbility
+import of10
+from of10 import *
+for modname in of10.__all__:
+    sys.modules["oftest." + modname] = sys.modules["of10." + modname]