empty non-terminal support

When looking for a name in tree, return wether we got to a longer one -

if so we had an ent. Add tests + dnssec tests and refactor the tests as

well a bit.

middleware/file/file_test.go

@@ -1,5 +1,16 @@
 package file
 
+import (
+	"strings"
+	"testing"
+)
+
+func BenchmarkParseInsert(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		Parse(strings.NewReader(dbMiekENTNL), testzone, "stdin")
+	}
+}
+
 /*
 var testDir = filepath.Join(os.TempDir(), "caddy_testdir")
 var ErrCustom = errors.New("Custom Error")