should n_max be changed to maxiter?

[jgostick]

In the rsa function we use n_max to limit the number of spheres added. To be more consistent I think these should be changed to maxiter. Note that we use ncylinders in the cylinders function, but also have a maxiter to control how many times it iterates to find the desired porosity.

[jgostick]

I think n_max is correct. maxiter implies there is some trial-and-error going on, but really rsa just inserts spheres until the desired volume fraction is reach, or no more room is found. It's not really an iteration. I find that I do use the n_max argument quite often to get an image of just a few spheres.