Explain defining an interface class.
Explain defining an interface class.

git-svn-id: 24f545668198cdd163a527378499f2123e59bf9f@1295 ead46cd0-7350-4e37-8683-fc4c6f79bf00

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