Synopsis
		sfsplit verb=n inp= outdir=(out_basenm+ivlad.ext nthick=1

Usage:

sfsplit inp=file.rsf outdir=[file_split.rsf] nthick=[1]

Parameter nthick gives the maximum thickness of a slice. The last slice may
be thinner.

Parameters
		string inp= ifile.rsf   int nthick=1 slice thickness   string outdir=(out_basenm+ivlad.ext   bool verb=n [y/n]