Rewrite in c

Thought I'd start this process now, as there is a whole lot to review.

Thus far, I've got clib(1) as nothing but an arbiter.  It supports any subcommand on `PATH`, and switches for `--help` and `--version`.  clib-install(1) acts just like the node impl, but will also install dependencies.  [clib-search(1)](https://github.com/stephenmathieson/clib-search) still needs a bit of work, but will be added here shortly.

Will close #8 and #2.