content: Strings bench/test +2700% perf improvement
util: No need for further Diffing if the two strings are equal.

diff --git a/util/diff.go b/util/diff.go
index 26e5594..00ba738 100644
--- a/util/diff.go
+++ b/util/diff.go
@@ -44,6 +44,9 @@ func mDiff(av, bv []string) (ret []string) {
 }

 func Diff(a, b string) string {
+	if a == b {
+		return ""
+	}
 	a = strings.Replace(a, "\r", "", -1)
 	b = strings.Replace(b, "\r", "", -1)
 	return strings.Join(mDiff(strings.Split(a, "\n"), strings.Split(b, "\n")), "\n")
clang: Benchmark for mm5.in.