fix glitch in dict.keys/values/items() optimisation for subtype calls under Python 3: called object method instead of supertype method

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extra : transplant_source : %94%87%D7e%B9%82%EF%926%26o%C0%8E%0DcY%C3%E3n%DB

fix some typos

convert cygdb to a distribute entry point

Conflicts:
	CHANGES.rst

int -> Py_ssize_t in cpython pxd files

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extra : rebase_source : 6494c60e7f79a9cc85fe72a7adf325557f6de2be

remove 'from datetime cimport *' line from cpython/__init__.pxd as it refers to a separate module, not the core C-API

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extra : rebase_source : bafa0a661abe97868fe254b3ce2b5e63b8654990

remove 'from datetime cimport *' line from cpython/__init__.pxd as it refers to a separate module, not the core C-API

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extra : rebase_source : bafa0a661abe97868fe254b3ce2b5e63b8654990

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extra : rebase_source : 6494c60e7f79a9cc85fe72a7adf325557f6de2be

This reverts commit 12d7dbb3.