Add a release candidate channel

[jwir3]

It would be nice if we had some form of a "release candidate" or "canary" type channel. This would allow us to test things without deploying a breaking change to npm.

[jwir3]

NOTE: This is partially fixed by #20, but there are still a few things broken:

1. We don't yet have a running test suite on the CI system. This is probably more work than 2, because it requires that we setup an SSH server, via a bunch of monkeying around, run our tests against this, and then terminate the SSH server. Much of what is broken right now really is the authentication system to the SSH server, which is likely not setup correctly.
2. We don't have any way of "pushing" a release candidate. This will likely require that we push -rcXX releases to npmjs.com, but we need to make sure that a version of 0.1.8 overrides 0.1.8-rc1.