changed out_file to positional input and added new tests
changed out_file to positional input and added new tests

glatard/nipype,gerddie/nipype,iglpdc/nipype,dgellis90/nipype,pearsonlab/nipype,sgiavasis/nipype,FCP-INDI/nipype,mick-d/nipype,dgellis90/nipype,wanderine/nipype,sgiavasis/nipype,pearsonlab/nipype,gerddie/nipype,FCP-INDI/nipype,sgiavasis/nipype,iglpdc/nipype,gerddie/nipype,mick-d/nipype,wanderine/nipype,mick-d/nipype,carolFrohlich/nipype,glatard/nipype,pearsonlab/nipype,FCP-INDI/nipype,pearsonlab/nipype,iglpdc/nipype,dgellis90/nipype,dgellis90/nipype,gerddie/nipype,carolFrohlich/nipype,wanderine/nipype,glatard/nipype,carolFrohlich/nipype,carolFrohlich/nipype,iglpdc/nipype,sgiavasis/nipype,wanderine/nipype,mick-d/nipype,FCP-INDI/nipype,glatard/nipype