Small changes to dual regression script

Hi Cindee,

I just made a small change to the dual regression scripts to allow for saving out the residuals image during dr stage 2. The main reason for this would be if you plan on using 3dClustSim in order to get the cluster size necessary for multiple comparisons correction. This requires getting smoothness estimate from each subject's residuals. Otherwise, I just made a couple minor changes to the user script which shouldn't affect functionality. No rush on looking at these though.

Thanks,
Jeremy