Add logic to Always Route updates to all servers

This patch would allow updates to go to clients that may have
disconnected from one server and connected to a new server without the
socket connection fully timing out.
bug #171

Adjust data size to 4096
Merge branch 'dev' of github.com:mozilla-services/pushgo into bug/data-size
Updated CHANGELOG
Merging #172.
Merge pull request #170 from mozilla-services/feature/alwaysRoute

Add `AlwaysRoute` option
Gracefully close HTTP and WebSocket connections.
Split up WebSocket, update, and health handlers.

* Move `sendClientCount()` to `Application`.
* Refactor `RealStatusHandler`.
Move locator health check to `Router.Status()`.

Closes #156.