MAINT: Replace PyStringObject by PyBytesObject.
MAINT: Replace PyStringObject by PyBytesObject.

This replaces the npy_3kcompat macro PyStringObject with its definition.

anntzer/numpy,anntzer/numpy,endolith/numpy,grlee77/numpy,jakirkham/numpy,grlee77/numpy,mhvk/numpy,seberg/numpy,simongibbons/numpy,jakirkham/numpy,simongibbons/numpy,jakirkham/numpy,mattip/numpy,madphysicist/numpy,jakirkham/numpy,numpy/numpy,simongibbons/numpy,pdebuyl/numpy,mhvk/numpy,anntzer/numpy,numpy/numpy,simongibbons/numpy,seberg/numpy,endolith/numpy,numpy/numpy,madphysicist/numpy,grlee77/numpy,pdebuyl/numpy,mhvk/numpy,pdebuyl/numpy,madphysicist/numpy,numpy/numpy,endolith/numpy,charris/numpy,madphysicist/numpy,simongibbons/numpy,rgommers/numpy,mattip/numpy,charris/numpy,grlee77/numpy,rgommers/numpy,mattip/numpy,anntzer/numpy,pdebuyl/numpy,jakirkham/numpy,mhvk/numpy,grlee77/numpy,charris/numpy,mhvk/numpy,pbrod/numpy,pbrod/numpy,pbrod/numpy,seberg/numpy,pbrod/numpy,endolith/numpy,seberg/numpy,rgommers/numpy,madphysicist/numpy,rgommers/numpy,pbrod/numpy,charris/numpy,mattip/numpy