WOMBAT: replace max intrinsics with arrays?

[dougiesquire]

There are a few locations in WOMBATlite/mid where the max intrinsic is used with an array argument. But from @JhanSrbinovsky over here:

reading again max(wombat%seddic(:,:) this might not be advisable. MAX() usually handles scalars a full array might require MAXVAL()

[dougiesquire]

The use of max in these instances is fine because it's an elemental function. However, array = max(array, min_val) will create a temporary copy so is possibly not ideal for large arrays. We should consider replacing with the where construct