doc: clarify nipy slice timing
doc: clarify nipy slice timing

gerddie/nipype,JohnGriffiths/nipype,Leoniela/nipype,glatard/nipype,fprados/nipype,Leoniela/nipype,dgellis90/nipype,rameshvs/nipype,carlohamalainen/nipype,mick-d/nipype_source,mick-d/nipype,carolFrohlich/nipype,carlohamalainen/nipype,FredLoney/nipype,wanderine/nipype,rameshvs/nipype,mick-d/nipype_source,wanderine/nipype,FCP-INDI/nipype,rameshvs/nipype,glatard/nipype,blakedewey/nipype,dmordom/nipype,grlee77/nipype,sgiavasis/nipype,grlee77/nipype,iglpdc/nipype,pearsonlab/nipype,FredLoney/nipype,gerddie/nipype,gerddie/nipype,carolFrohlich/nipype,grlee77/nipype,FCP-INDI/nipype,FCP-INDI/nipype,mick-d/nipype,JohnGriffiths/nipype,dgellis90/nipype,rameshvs/nipype,dgellis90/nipype,arokem/nipype,blakedewey/nipype,pearsonlab/nipype,blakedewey/nipype,carolFrohlich/nipype,FCP-INDI/nipype,Leoniela/nipype,wanderine/nipype,arokem/nipype,carlohamalainen/nipype,iglpdc/nipype,blakedewey/nipype,iglpdc/nipype,FredLoney/nipype,gerddie/nipype,glatard/nipype,dgellis90/nipype,glatard/nipype,wanderine/nipype,grlee77/nipype,fprados/nipype,fprados/nipype,dmordom/nipype,pearsonlab/nipype,iglpdc/nipype,sgiavasis/nipype,arokem/nipype,sgiavasis/nipype,JohnGriffiths/nipype,pearsonlab/nipype,arokem/nipype,carolFrohlich/nipype,dmordom/nipype,mick-d/nipype,mick-d/nipype_source,mick-d/nipype,sgiavasis/nipype,JohnGriffiths/nipype