Added all PyTypeObjects to the appropriate header files.
Before the patch a lot of internal types weren't available in the header files. The patch exposes the new iterators, views and some other types to all C modules. I've also renamed some of the types and tp_names.
diff --git a/Include/setobject.h b/Include/setobject.h
index 8914749..5b97fcb 100644
--- a/Include/setobject.h
+++ b/Include/setobject.h
@@ -58,6 +58,7 @@
 
 PyAPI_DATA(PyTypeObject) PySet_Type;
 PyAPI_DATA(PyTypeObject) PyFrozenSet_Type;
+PyAPI_DATA(PyTypeObject) PySetIter_Type;
 
 /* Invariants for frozensets:
  *     data is immutable.