Fix buffer pure mode regression.
Speccial case the unused '_' in warnings.
Remove archaic disable_function_redefinition option.
Use wraparound and boundscheck directives for memory view slices.
prevent unused '_' variables from appearing in C code
report unused variables also across closures
reduce code overhead in some utility functions
replace some more Python string constants in utility code
inline PyList_Append() a bit more
changelog
remove spurious Py_DECREF(None) from 'raise ... from None' code
minor formatting fixes
extend test case
fix long-standing bug that dict.items() etc. returned lists also in Py3
changelog
make entries keep their utility code when inheriting them from cdef base classes
fix test after changing dict.keys() in Py3
fix dir() implementation to always return a sorted list
make SortedDictKeysNode look more like other pass-through nodes
avoid list building when in-testing against dir() result