analyse loop variable in scoped comprehensions as local variable (enables control flow based optimisations)

Fix __Pyx_ImportType if #Py_LIMITED_API is defined.

Fix first example in memoryview docs

prevent special __weakref__ attribute from triggering generation of garbage collection code for the type

--HG--
rename : tests/run/function_as_method_T494.pyx => tests/run/function_as_method_py_T494.py

drop 'vile hack' by restricting state changes of AttributeNode during infer_type() to what analyse_types() does

fix warning about unused temp variable when both FlattenInListTransform and SwitchTransform are applied