Use the [SockJS Protocol](https://github.com/sockjs/sockjs-protocol) to handle
bidirectional communication instead of plain websockets. This allows
distributed queries to function in situations in which they previously failed
(Load balancers not supporting websockets, issues with Safari and self-signed
certs, etc.).
Also includes fixes to the JS message handling logic where slightly different
message delivery semantics (when using XHR) were exposing bugs.
Fixes#1241, #1327.
* Defining a concrete type for session tokens
* More rightish vc.IsLoggedIn()
* using type conversion instead of a method call
* include sessions in test viewer contexts
- New route `/api/v1/kolide/results/{id}` with upgrade to websocket connection
- Query results pushed over websocket as they are received from pubsub
- Target totals updates pushed over websocket every second
- New datastore method to support retrieiving target totals
- Websocket package includes helpers and patterns for communicating over websockets
