Implement multi-scheduler:

1. Name default scheduler with name `kube-scheduler`
2. The default scheduler only schedules the pods meeting the following condition:
	- the pod has no annotation "scheduler.alpha.kubernetes.io/name: <scheduler-name>"
	- the pod has annotation "scheduler.alpha.kubernetes.io/name: kube-scheduler"

update gofmt

update according to @david's review

run hack/test-integration.sh, hack/test-go.sh and local e2e.test

pkg/api/types.go

@@ -2218,3 +2218,8 @@ type RangeAllocation struct {
 	// a single allocated address (the fifth bit on CIDR 10.0.0.0/8 is 10.0.0.4).
 	Data []byte `json:"data"`
 }
+
+const (
+	// "default-scheduler" is the name of default scheduler.
+	DefaultSchedulerName = "default-scheduler"
+)