We really need to make these enabled by command line flags...

May revert depending on what the final decision is for this slot.

extended test case: test that common method forwarding patterns still work with the new special method setup code

extended test case: test that common method forwarding patterns still work with the new special method setup code

Fix #561 doctests to work under Python 2 and 3; remove problematic doctest from type_slots_int_long_T287.pyx