MAINT: Remove messy handling of output tuple in np.unique
MAINT: Remove messy handling of output tuple in np.unique

Largely taken from gh-9531

jorisvandenbossche/numpy,abalkin/numpy,endolith/numpy,mhvk/numpy,WarrenWeckesser/numpy,mattip/numpy,madphysicist/numpy,jorisvandenbossche/numpy,numpy/numpy,MSeifert04/numpy,abalkin/numpy,pizzathief/numpy,anntzer/numpy,grlee77/numpy,MSeifert04/numpy,Eric89GXL/numpy,gfyoung/numpy,tynn/numpy,gfyoung/numpy,WarrenWeckesser/numpy,seberg/numpy,mhvk/numpy,anntzer/numpy,pizzathief/numpy,MSeifert04/numpy,shoyer/numpy,simongibbons/numpy,mhvk/numpy,mattip/numpy,Eric89GXL/numpy,seberg/numpy,pbrod/numpy,pbrod/numpy,anntzer/numpy,abalkin/numpy,pdebuyl/numpy,grlee77/numpy,rgommers/numpy,gfyoung/numpy,madphysicist/numpy,simongibbons/numpy,numpy/numpy,tynn/numpy,mhvk/numpy,mattip/numpy,ahaldane/numpy,pizzathief/numpy,rgommers/numpy,charris/numpy,jakirkham/numpy,madphysicist/numpy,pdebuyl/numpy,grlee77/numpy,jakirkham/numpy,charris/numpy,rgommers/numpy,pdebuyl/numpy,pbrod/numpy,pbrod/numpy,shoyer/numpy,grlee77/numpy,grlee77/numpy,WarrenWeckesser/numpy,ahaldane/numpy,rgommers/numpy,Eric89GXL/numpy,endolith/numpy,shoyer/numpy,seberg/numpy,pbrod/numpy,jakirkham/numpy,ahaldane/numpy,MSeifert04/numpy,jorisvandenbossche/numpy,shoyer/numpy,seberg/numpy,jakirkham/numpy,numpy/numpy,endolith/numpy,tynn/numpy,numpy/numpy,shoyer/numpy,jakirkham/numpy,madphysicist/numpy,simongibbons/numpy,mhvk/numpy,simongibbons/numpy,charris/numpy,endolith/numpy,jorisvandenbossche/numpy,madphysicist/numpy,WarrenWeckesser/numpy,MSeifert04/numpy,ahaldane/numpy,charris/numpy,pizzathief/numpy,Eric89GXL/numpy,ahaldane/numpy,simongibbons/numpy,mattip/numpy,pdebuyl/numpy,anntzer/numpy,jorisvandenbossche/numpy,WarrenWeckesser/numpy,pizzathief/numpy