DOC: Document deprecation of C-API functions
DOC: Document deprecation of C-API functions

These functions are believed to be unused, or at least largely
unused.

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