Add board and stream list functionality

### Features
* New toolbar
* Boards can be listed
* Streams can be listed

### Compatibility Issues
* Existing database of random title-less boards needs a cleanup
* Switch to Angular routing means old URLs won't work
The assert ensures that you don't save a different board's json blob to this one.  Remember that initially board IDs were created not through /new/ but by visiting /index/, so a board's ID gets assigned from the moment it was created.

If we're changing that (boards are created on a save post-/new/), we might have to change how we set IDs, etc.