Include tests for lye:check/2, fix for bug.

In my hubris I failed to test the public function. Wouldn't you know it,
dialyzer wasn't enough to check the type error and, not having actually _run_
the function from the REPL neither did I.

Signed-off-by: Brian L. Troutwine <brian@troutwine.us>
Include usage information in the README.

The REPL interaction is a bit ugly. Having an `examples/` would be a Good Idea.

Signed-off-by: Brian L. Troutwine <brian@troutwine.us>
Merge pull request #3 from blt/readme_update_usage

Include usage information in the README.
Merge pull request #2 from blt/deep_list_fix

Include tests for lye:check/2, fix for bug.