ENH Added grad_dev input to fsl.dti.bedpostx5 interface

[mattfeld]

bedpostx expects a grad_dev.nii.gz file in subject directory if the -g flag is true.

I've tested these changes locally running a bedpostx workflow successfully on the HCP data.

[coveralls]

Coverage decreased (-0.009%) to 72.074% when pulling cf77312 on mattfeld:master into 53cf6f8 on nipy:master.

[coveralls]

Coverage decreased (-0.005%) to 72.078% when pulling cf77312 on mattfeld:master into 53cf6f8 on nipy:master.

[satra]

if isdefined(self.inputs.grad_dev):
    _, _, ext = split_filename(self.inputs.grad_dev)
    copyfile(self.inputs.grad_dev, os.path.join(subjectdir, 'grad_dev' + ext))

[satra]

thanks @mattfeld , the comment takes care of the situation when the grad_dev is not defined. also, if you could run make_specs and add the updated test_auto_bedpostx file that would be good.

[mattfeld]

thanks @satra for your comment. I've added the if statement for times when grad_dev is not defined, ran the make specs and updated the test_auto_BEDPOSTX5.py file. Let me know if there is anything else I need to do.