Fixed tracking specs
streamline outputs generation
mandatory cannot be false
Merge pull request #809 from chrisfilo/fix/mrtrix_prob_spec

Important bugfix for MRTrix tracking
Fixed bug in FSL DTIFit interface
Fix for stop argstr in MRtrix's Streamtrack interface
Updated test for DTIfit
Updated tests for streamtrack-derived interfaces
Merge pull request #812 from swederik/bf/dtifit

Fixed bug in FSL DTIFit interface
Merge pull request #814 from swederik/bf/streamtrack

Fix for stop argstr in MRtrix's Streamtrack interface