ANTs visualization module

There is still a lot that needs to be done, and I'm still working on this so please bear with me.
@satra could you please help me here: this interface does not produce an output file, i.e after running the node the expected output file is not in the subject's folder. However, if I just copy and paste the produced command line, everything goes smoothly. 
This is the report from this node when testing 
Node: slicer (ants)                                                                                                                                                              
===================

 Hierarchy : hc_addition.slicer
 Exec ID : slicer.a0

Original Inputs
---------------

* alpha_value : 0.5 
* args : <undefined>
* direction : 2 
* environ : {'NSLOTS': '1'}
* flip_slice : <undefined>
* ignore_exception : False
* input_image : /NMOMVPA/subjects/test/T1.nii.gz
* mask_image : /NMOMVPA/working/hc_addition/_subject_id_test/fsl_bet/T1_brain_mask.nii.gz
* num_threads : 1 
* output_image : <undefined>
* pad_or_crop : mask+2
* permute_axes : <undefined>
* rgb_image : /NMOMVPA/working/hc_addition/_subject_id_test/converter/rgb.nii.gz
* slices : [2,mask-2,mask+2]
* terminal_output : stream
* tile_geometry : -1x8

Execution Inputs
----------------

* alpha_value : 0.5 
* args : <undefined>
* direction : 2 
* environ : {'NSLOTS': '1'}
* flip_slice : <undefined>
* ignore_exception : False
* input_image : /NMOMVPA/subjects/test/T1.nii.gz
* mask_image : /NMOMVPA/working/hc_addition/_subject_id_test/fsl_bet/T1_brain_mask.nii.gz
* num_threads : 1 
* output_image : <undefined>
* pad_or_crop : mask+2
* permute_axes : <undefined>
* rgb_image : /NMOMVPA/working/hc_addition/_subject_id_test/converter/rgb.nii.gz
* slices : [2,mask-2,mask+2]
* terminal_output : stream
* tile_geometry : -1x8

Execution Outputs
-----------------

* output_image : <undefined>