diag/net: visualizing in d3 and dot

refactor(fsrepo.FSRepo): manage the Datastore and daemon.lock

"for each desired change, make the change easy (warning: this may be
hard), then make the easy change" - Kent Beck

https://twitter.com/KentBeck/status/250733358307500032

http://martinfowler.com/articles/preparatory-refactoring-example.html

cc @jbenet @whyrusleeping

The struct was getting unmanageable. extracted the config component to
reduce complexity. The datastore will be written as another component.

fix(fsrepo): extract private, unsynced method to prevent deadlock

no issue detected but it's good to be safe

NB: daemon is one spot the repo lock is typically acquired

for now, allow daemon and client to both hit config

@jbenet @whyrusleeping thoughts?

Try it out:

```
ipfs net diag --vis=d3 | diagnostics/d3/d3view
```

Notes: this is not the best way to do it, because it
breaks `--encoding=json`. Not sure what the best way is, and
right now this provides more utility than the other.

the travis docs say the env flag TRAVIS=true but, i want
to make absolutely sure. explicitness leaves less room for
error.

Serial File Opening

Stdin Input