You can use `nix-env` to install any derivation that outputs binaries underneath
a `bin/` directory, so we can reuse `nix-env` for installing binaries built by
this project.
* Update tests.patch
* release.nix fixes for building and running cabal test suite from inside the nix-shell environment
* Update build instructions
* More README updates
* Fix stack tooling and improve documentation
* Update grpc sha256, cleanup build instructions
* Whups, DYLD_LIBRARY_PATH and substituteInPlace is still needed for hydra / macos builds with no brew-installed grpc!
* PR feedback tweaks