`raster_calculator`'s raster dimensions checking doesn't list filepaths that differ

[phargogh]

When running raster_calculator with rasters of 2 different resolutions, the exception lists the raster sizes but not which sizes belong to which rasters. This information is available to us, so it'd be nice to make a more helpful error message and make it easier to debug.

[megannissel]

Addressed in #430