Adapted to Earth Engine API changes (Mar. 31)

• Google announced a while back that they are changing the JS and Python API to be supported by it's Cloud API
• For me, that change broke several things, both in Python and in JS:
• I was suddenly unable to d/l any geotiffs from EE to make models from, which took time to figure out.
• Even then, none of my hillshade overlays showed up, again, that took some time to fix.
• Impact: 
• There was an outage of a couple of days that prevented any d/l. Several users got in contact with me; if you've been affected - I'm sorry!
• But, nobody complained about the lack of hillshade overlays :)
• Google has apparently decided to lower the maximum size that can be downloaded. It should not affect TouchTerrain, b/c I only request appropriately downsampled geotiffs from them anyway and our server also caps how many pixels you can process on it, but I have not tested this well. It's possible that users will run into the Google quota if they request very large models.
• But, that pretty much kills the "download at source resolution" option I had and so I took it out. It's still available in standalone to make models at the exact same resolution as a local raster (geotiff). 
• It is still possible to "export" large rasters into something running in the Google Cloud but I have no intentions to run our server in the Google cloud. At least not for the foreseeable future.
• Silver lining: After going back to digging around the Earth Engine API I noticed a whole bunch of new terrain and terrain related datasets!  My next plan is to add some of these to Touchterrain.