Arti API exploration to build example tools

Some programs should be created and curated using Arti to illustrate to other developers how they can use its APIs and to also find bugs. This includes 3 example programs to let developers get their feet wet with Arti and 2 bigger projects which would have a legitimate, production use case and can benefit from all that Arti provides, even in its current infancy. There will also be documentation improvements made, especially to APIs that these example projects rely on, in order to more directly contribute upstream to Arti.