Afrouterd contextualization.

- Removed connect loop in favour of grpc-implemented backoff.
- Added context that is passed to all subprocesses, and canceled when the connection to the afrouter is lost.
- On afrouter re-connect, everything is stopped, and the system starts over from a clean slate.

Resolves VOL-1681.
Possibly resolves VOL-1655 & VOL-1661, please retest.

Change-Id: I92e16ac02b2ba209570d25ac407515d2df1c7b22
diff --git a/Gopkg.lock b/Gopkg.lock
index eaa2bb4..0749a6c 100644
--- a/Gopkg.lock
+++ b/Gopkg.lock
@@ -810,6 +810,7 @@
     "google.golang.org/grpc/connectivity",
     "google.golang.org/grpc/credentials",
     "google.golang.org/grpc/grpclog",
+    "google.golang.org/grpc/keepalive",
     "google.golang.org/grpc/metadata",
     "google.golang.org/grpc/status",
     "gopkg.in/Shopify/sarama.v1",