DOC: Added note about base attribute
DOC: Added note about base attribute

mattip/numpy,charris/numpy,jakirkham/numpy,numpy/numpy,jakirkham/numpy,anntzer/numpy,pdebuyl/numpy,mhvk/numpy,rgommers/numpy,endolith/numpy,charris/numpy,anntzer/numpy,numpy/numpy,seberg/numpy,anntzer/numpy,mhvk/numpy,endolith/numpy,endolith/numpy,charris/numpy,seberg/numpy,rgommers/numpy,pdebuyl/numpy,rgommers/numpy,seberg/numpy,endolith/numpy,seberg/numpy,mattip/numpy,jakirkham/numpy,mhvk/numpy,mattip/numpy,numpy/numpy,anntzer/numpy,rgommers/numpy,mhvk/numpy,mattip/numpy,jakirkham/numpy,pdebuyl/numpy,jakirkham/numpy,mhvk/numpy,pdebuyl/numpy,numpy/numpy,charris/numpy