LwSrc i,j bug

[jcwarner]

For the LwSrc, in step3d_t.F near lines 1146 we need to change
cff=dt(ng)*pm(i,j)*pn(i,j)
to
cff=dt(ng)*pm(Isrc,Jsrc)*pn(Isrc,Jsrc)

and the same near lines 1343 from
cff=dt(ng)*pm(i,j)*pn(i,j)
to
cff=dt(ng)*pm(Isrc,Jsrc)*pn(Isrc,Jsrc)

-j

[arango]

Thanks, John, great catch. Weird, my aggressive compiling/linking flags didn't pick up those out-of-bounce indices in parallel. I will update the code.