Issue python#127: Fix pickling and copying of various types. Fix pickling tests.

This change is based on f5f98595c6cc63b from 2.7-slp, but it is heavily modified for Python 3.

- Pickle 'callable-iterator' objects correctly. Previously the unpickled object had the type '_stackless._wrap.callable-iterator'.

- Fix pickling of 'method-wrapper' objects. Previously pickling them caused a SystemError exception.

- Fix copy.copy() for 'callable-iterator', 'method', 'dict_keys', 'dict_values' and 'dict_items' objects. Previously the copied object had the type '_stackless._wrap....'.

- Fix Stackless pickling tests. The method StacklessTestCase.dumps() didn't pass the pickle protocol to the pickler.

- Remove dead code in prickelpit.c. The code was used in older Stackless versions.

Author: Anselm Kruis

Stackless/changelog.txt

@@ -9,6 +9,11 @@ What's New in Stackless 3.X.X?
 
 *Release date: 20XX-XX-XX*
 
+- https://bitbucket.org/stackless-dev/stackless/issues/127
+  Fix pickling of 'callable-iterator' and 'method-wrapper' objects.
+  Fix copy.copy() for 'callable-iterator', 'method', 'dict_keys', 'dict_values'
+  and 'dict_items' objects.
+
 - https://bitbucket.org/stackless-dev/stackless/issues/126
   Load the module stackless early in all C-Python tests. This ensures a defined
   behaviour of the tests even, if the execution order gets randomised.