Replaces the existing calculation that uses a global online interval. This method was lacking due to the fact that different hosts may have different checkin intervals set.
The new calculation uses `min(distributed_interval, config_tls_refresh) + 30` as the interval. This is calculated with the stored values for each host.
Closes#1321
Push the calculation of target counts into the SQL query, rather than loading
all of the targets and then counting them. This provides a dramatic (>100x)
speedup in loading of the manage packs page when large numbers of hosts are
present.
Closes#1426
Notable refactoring:
- Use stdlib "context" in place of "golang.org/x/net/context"
- Go-kit no longer wraps errors, so we remove the unwrap in transport_error.go
- Use MakeHandler when setting up endpoint tests (fixes test bug caught during
this refactoring)
Closes#1411.
- 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
