[Therion] infer plumbs

Hello "infer plumbs on" not affected to vertical shot correction with loop closure Example: ==== source survey test centerline infer plumbs on 1 2 10 0 0 2 3 10 - down 3 4 10 0 0 4 5 20 150 0 5 6 10 - up equate 1 6 endcenterline endsurvey endsource export model ==== -- WBR, Vasily