Synopsis
		sfpwarp < inp.rsf other=oth.rsf > shift.rsf ishift=ishift.rsf niter=5 liter=20 rect1=1 rect2=1 order=1 drift=n verb=n eps=0.0f

Parameters
		bool drift=n [y/n] if shift filter   float eps=0.0f regularization   string ishift= initial shift (auxiliary input file name)   int liter=20 number of linear iterations   int niter=5 number of iterations   int order=1 accuracy order   file other= auxiliary input file name   int rect1=1 shift smoothness on 1st axis   int rect2=1 shift smoothness on 2nd axis   bool verb=n [y/n] verbosity flag