Provide an implicit version, for Scala clients.
Great big directory layout revamp.

This groups modes, services, and libraries into separate directories. Things
were getting a bit out of hand at the top level.

Everything is still hidden behind one or more profiles, and the "provided"
naming scheme will probably rub some people the wrong way, but I prefer
modes/scala to modes/scala-mode even though the Github project happens to be
scala-mode.

I'll update the README at some point, but more likely it will be to say "use
this script to check out the bootstrap projects" because enumerating them is
getting cumbersome.