added xor and requires metadata spec to devel docs
added xor and requires metadata spec to devel docs

git-svn-id: 24f545668198cdd163a527378499f2123e59bf9f@1387 ead46cd0-7350-4e37-8683-fc4c6f79bf00

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