updated test case to use the new step_record output
debugged interpolation code in pismo
cache more variables in preparation for interpolation, and debugged the associated caching code
hooked interpolation of some NMS data points
this was intended to be included in the last commit -- just commented out some debug printfs
use pism's column-major array storage.  Also added a bunch of debugging code that is currently commented out, but may be helpful in the future.
don't use the skipping mechanism for now, since I don't really know how to come up with a good skip_max value.
debugged inerpolation of boundary conditions.  Code is a bit of a mess right now, but it seems to be working more or less