Initial delivery of metrics code (#81)

* Initial delivery of metrics code

* Fix build issues

* Fix build issue with go vet

vendor/golang.org/x/crypto/md4/example_test.go

@@ -1,20 +0,0 @@
-// Copyright 2017 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package md4_test
-
-import (
-	"fmt"
-	"io"
-
-	"golang.org/x/crypto/md4"
-)
-
-func ExampleNew() {
-	h := md4.New()
-	data := "These pretzels are making me thirsty."
-	io.WriteString(h, data)
-	fmt.Printf("%x", h.Sum(nil))
-	// Output: 48c4e365090b30a32f084c4888deceaa
-}