Renamed `/node_lib` -> `/lib`
Snapshot
Removed orientdb
Moved `http.js` to `browser/` and cleared out `lib/`
Moved `express` and `freeport` deps to `browser/`
Code and partial tests for `LinksDb`

`LinksDb` represents the Links application database. It is initialized
with a backend that provide access to an actual database, and
communicates with that backend using the interface defined in
`test/interfaces/Backend.js`.

This commit includes tests of `LinksDb#ensureDb()`.
`RethinkDb`, which implements `Backend`, without tests
Notes on how to mock the RethinkDb driver
Removed errant, unused Buster.js dev dependency
Wrote tests for and fixed problems with `RethinkDb.js`
Merge branch 'try-again'