Update README.md

Hand over copyright to FSF

Include URL in header

Remove unused binding

If cargo not found, log and fail gracefully rather than erroring

Fix minor typos in docstrings

Explicity require json library

Rename clippy-flymake to flymake-clippy

Update README.md

Update README.md

Introduce `clippy-flymake-cargo-path' as a custom user option

Minor code style changes

Fallback message level to :note

Hide the Clippy process buffer from `C-x b'

Update documentation