Initial sharing

This is all of the work that's gone into adding sharing to Crypton as well as some ergonomic changes. It includes:

 * initial Inbox support
 * a CLI
 * chat examples
 * documentation
 * container deletion
 * transaction bugfixes

Things sharing still needs:

 * extensive testing
 * finished container sharing
 * message deletion

We're merging this in to provide a blank slate and allow for more focused sprints (instead of depending on a monolithic dev branch), and to better highlight the current state of the framework.