Csm sandbox v2

[jrcain-usgs]

Closes #110 (The csm sandbox issue)
Closes #134 (The old PR for the same issue).
Differences from the old PR:

• Made flickering less bad (none in native jupyter notebook on my machine)
• ISD based on full-sized CTX image (not a tiny crop)
• ISD Value comparison table
• Downloadable zip with notebook + ISD

Licensing

This project is mostly composed of free and unencumbered software released into the public domain, and we are unlikely to accept contributions that are not also released into the public domain. Somewhere near the top of each file should have these words:

This work is free and unencumbered software released into the public domain. In jurisdictions that recognize copyright laws, the author or authors of this software dedicate any and all copyright interest in the software to the public domain.

• I dedicate any and all copyright interest in this software to the public domain. I make this dedication for the benefit of the public at large and to the detriment of my heirs and successors. I intend this dedication to be an overt act of relinquishment in perpetuity of all present and future rights to this software under copyright law.

[Kelvinrr]

why is there a second PR? Can we close the old one?

[jrcain-usgs]

In the first one I moved around some files, and worked a bit in the wrong direction. It was simpler to just make a new PR. The old one will be closed when this one is merged.

[Kelvinrr]

A few changes I would push for.

Overall, exactly what we needed, this is genuinely insightful to play with.