feat(daemon) `ipfs daemon --initialized`

With this PR, users can fetch and run ipfs in _one_ command.

```
docker run -d -p 4001:4001 -p 5001:5001 jbenet/go-ipfs daemon --initialized
```

Magic.

nb: needs https://github.com/jbenet/go-datastore/pull/9
> Woah, while I'm glad you made sure to close the internal ContextCloser (and didn't override without lookin)

Yeah, to mitigate the risk of overriding without looking, it's best to keep things as explicit as possible. I don't think giving the context closer responsibility for synchronous close operations is a good road to follow.