Synopsis
		sflinsincos < in.rsf > out.rsf s0= na= da= oa= nt=180 dt=2. ot=0. nr=nvx/2 dr=dvx extend=4

Parameters
		float da= angle sampling.   float dr=dvx radius sampling.   float dt=2. polar angle sampling.   int extend=4 tmp extension   int na= number of angle values.   int nr=nvx/2 number of radius on radial lines   int nt=180 number of polar angle for integration.   float oa= angle origin   float ot=0. polar angle origin   float s0= reference slowness