migrate from MODIS to ... sentinel2

[profLewis]

Given that MOSIS will soon finish collecting data, the examples and c/w should probably be re-developed fro some other data source. Something with Sentinel-2 time series would be interesting.

A simpler job would be to migrate to VIIRS, which no doubt has a similar snow and LAI product.

I leave this for the next convenor of the course to manage.