Add TLS resolver connection reusing and pooling

Also, fix caching issues and add more tests

resolver/namerecord_test.go

@@ -0,0 +1,27 @@
+package resolver
+
+import "testing"
+
+func TestNameRecordStorage(t *testing.T) {
+	testDomain := "Mk35mMqOWEHXSMk11MYcbjLOjTE8PQvDiAVUxf4BvwtgR.example.com."
+	testQuestion := "A"
+
+	testNameRecord := &NameRecord{
+		Domain:   testDomain,
+		Question: testQuestion,
+	}
+
+	err := testNameRecord.Save()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	r, err := GetNameRecord(testDomain, testQuestion)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if r.Domain != testDomain || r.Question != testQuestion {
+		t.Fatal("mismatch")
+	}
+}