Synopsis
		sfnpyCorr < Fa.rsf flt=Fb.rsf > Fc.rsf norm=n nc=100

Implements corr(a,b) along the fast axis
a [file] : is taken from stdin
b [file] : is taken from "flt"
Requires both files to have the same sampling interval

Parameters
		file flt= auxiliary input file name   int nc=100 number of correlation lags   bool norm=n [y/n] normalize output