NaN values can propagate through

[scotthavens]

During a simulation, a NaN value of cloud factor and elevation metadata made it all the way through SMRF. This made net_solar and thermal all NaN and SMRF continued to run. AWSM also continued to run for 3 months with no data values in the model and no errors from SMRF. The only reason that the simulation crashed was during a lidar update.

We should have some checks to just make sure that there are no NaN's in the input data or that there are no NaN values in the distributed results. I was able to resolve some of it in the loadGrid but this might be a good feature to have in loadData.