Remove as.matrix for slight efficiency?

[sfogarty]

https://github.com/Trinity-Automata-Research/dsmodels/blob/54790ee6646c0d3c678685365a5e20489dbb7212/R/dsrange.R#L97C5-L98

For a simple test case the result of expand.grid(gx,gy)[[1]] is equivalent to N[,1], so perhaps we should switch and use those? But maybe in some weird way they are different?