Don't need to keep a 'coords' array for the variable loop.
Save some grid-related parameters in the variable attributes.

This information may be useful for matching vertical descriptors, and for saving
variables back into FSTD files.
Factor out the step for attaching lat/lon coordinates.

Do this in a transformation function after the raw FSTD variables are created.
Minor bug fix - was storing 'ig2' value in 'ig1' attribute.
A degenerate vertical axis is a pressure axis, not a height axis.
Put raw IP1 values into the vertical axis of FSTD variables.

Will be decoded in a later stage.
Shorten the IAxis,JAxis,KAxis,XAxis,YAxis names to i,j,k,x,y.
Skip over derived variables when reducing dimensionality.
Shorten the derived 2D 'latitudes' and 'longitudes' fields to 'lat' and 'lon'.

This way, they're consistent with the axis names.
Start implementing vertical coordinates.

Still need to implement vgrid stuff (from !! record).