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

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extra : rebase_source : 562b717b9c1e078b3f83e3febc8addc1a29d85fe

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extra : rebase_source : 9ac699d2cd10ea7eef564c2790ad36c6474028f4

Update pyximport.py

this should be changed

PyArray_FROM_OTF and PyArray_FROM_OT should return type `object`

They were declared as returning type `bint`, but this appears to be incorrect.

http://docs.scipy.org/doc/numpy/reference/c-api.array.html#PyArray_FROM_OTF

http://docs.scipy.org/doc/numpy/reference/c-api.array.html#PyArray_FROM_OT

 external ref assignment

fix some typos

convert cygdb to a distribute entry point

added an option to set the gdb executable