Fnlb/k8s grouper (#563)

* WIP: add k8s grouper

- This shares a great deal of behaviour with allGrouper. Once it's
tested, refactor that to share as much as possible

- Glide hell. Checked in the yaml and lock files but a glide i -v
will be required to bring vendor/ up-to-date. Will address once this
is ready.

* Update README. Make the watch tracking work.

(To follow: add the junk that was pulled in via the glide update.)

* Vendor updates.

* go fmt

* Use the allGrouper with a k8s-backed DBStore instead.

This is much tidier :-)

* Fix up go vet

vendor/github.com/golang/protobuf/proto/lib.go

@@ -73,6 +73,7 @@ for a protocol buffer variable v:
 When the .proto file specifies `syntax="proto3"`, there are some differences:
 
   - Non-repeated fields of non-message type are values instead of pointers.
+  - Getters are only generated for message and oneof fields.
   - Enum types do not get an Enum method.
 
 The simplest way to describe this is to see an example.