[cmckn]

I didn't know about the autocomplete, that is really helpful; and I'm excited to see `ls` PR'd! Huge thanks to the contributors.

I think some of my cache misses were a rookie mistake: I was building a few expensive targets on a `FROM ...:latest` base. The base image changed often enough to make the cache misses annoying, but infrequent enough to make me think it was GC. My builds are much happier now! :)