Design Doc for Simulating Subset and Patch

https://docs.google.com/document/d/1DJ6VkUEZS2kvYZemIoX4fjCgqFXAtlRjpMlkOvblSts/edit?usp=sharing

The intent of this document is to specify a prototype version of the
protocol meant for quick implementation and iteration. The prototype
version will be used solely for simulation and analysis of the performance
of this approach.

In the last meeting we talked about the possibility of also having subset
and patch work with glyph id's, this document does not yet capture that
capability, but I plan to up date it to optionally support a glyph based
subset specification.

<https://docs.google.com/document/d/1DJ6VkUEZS2kvYZemIoX4fjCgqFXAtlRjpMlkOvblSts/edit?usp=sharing>