Most importantly, add option to use the pairwise L_infinity regularizer only in proximal space (use it for weight grouping/clustering, but not for determining the actual weight values nor clipping); this is important because the L_inf regularization penalty can be quite harsh and zero out features well before causing them to be grouped. This way, we can force fewer groups without forcing fewer features. Also, add option to exclude some features from the OSCAR regularizer altogether. Finally, add lots of debugging options to print the intermediate calculations during the proximal step.