Hopper fuzz tests, using cargo-fuzz.

If you'd like to run the tests please go back up to the top-level directory and do the following:

> docker build -t hopper-img . 
> docker run  -v $(pwd):/source -w /source -it hopper-img /bin/bash
> root@65d32c765696:/source# cargo fuzz run basic_fuzz

The basic_fuzz test will run forever.