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/proc_io_test.go

@@ -0,0 +1,33 @@
+package procfs
+
+import "testing"
+
+func TestProcIO(t *testing.T) {
+	p, err := FS("fixtures").NewProc(26231)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	s, err := p.NewIO()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	for _, test := range []struct {
+		name string
+		want int64
+		have int64
+	}{
+		{name: "RChar", want: 750339, have: int64(s.RChar)},
+		{name: "WChar", want: 818609, have: int64(s.WChar)},
+		{name: "SyscR", want: 7405, have: int64(s.SyscR)},
+		{name: "SyscW", want: 5245, have: int64(s.SyscW)},
+		{name: "ReadBytes", want: 1024, have: int64(s.ReadBytes)},
+		{name: "WriteBytes", want: 2048, have: int64(s.WriteBytes)},
+		{name: "CancelledWriteBytes", want: -1024, have: s.CancelledWriteBytes},
+	} {
+		if test.want != test.have {
+			t.Errorf("want %s %d, have %d", test.name, test.want, test.have)
+		}
+	}
+}