Input interpolation restricted by coarse grid size

[chowland]

This issue arises when upscaling a flow field from a previous simulation as an input file.

Currently, the stencil used for upscaling any variable on a refined grid (e.g. phi or sal) uses the existing variables irangc etc to calculate the indices. These are only allocated memory to match the size of the (new) base grid, so if the refined grid of the previous simulation is larger than this, the interpolation cannot be performed.

The input interpolation should use its own irangc variables (or allocate them with more memory first) to resolve this issue.