PLT-4357 adding performance monitoring (#4622)

* WIP

* WIP

* Adding metrics collection

* updating vendor packages

* Adding metrics to config

* Adding admin console page for perf monitoring

* Updating glide

* switching to tylerb/graceful

vendor/github.com/prometheus/procfs/stat_test.go

@@ -0,0 +1,14 @@
+package procfs
+
+import "testing"
+
+func TestStat(t *testing.T) {
+	s, err := FS("fixtures").NewStat()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if want, have := int64(1418183276), s.BootTime; want != have {
+		t.Errorf("want boot time %d, have %d", want, have)
+	}
+}