Fixed name encoding in adress headers

Closes #24.

gomail.go

@@ -12,7 +12,7 @@ import (
 	"sync"
 	"time"
 
-	"gopkg.in/alexcesaro/quotedprintable.v1"
+	"gopkg.in/alexcesaro/quotedprintable.v2"
 )
 
 // Message represents an email.
@@ -104,15 +104,11 @@ const (
 // SetHeader sets a value to the given header field.
 func (msg *Message) SetHeader(field string, value ...string) {
 	for i := range value {
-		value[i] = msg.encodeHeader(value[i])
+		value[i] = encodeHeader(msg.hEncoder, value[i])
 	}
 	msg.header[field] = value
 }
 
-func (msg *Message) encodeHeader(value string) string {
-	return msg.hEncoder.Encode(value)
-}
-
 // SetHeaders sets the message headers.
 //
 // Example:
@@ -138,10 +134,15 @@ func (msg *Message) FormatAddress(address, name string) string {
 	buf := getBuffer()
 	defer putBuffer(buf)
 
-	n := msg.encodeHeader(name)
-	if n == name {
+	if !quotedprintable.NeedsEncoding(name) {
 		quote(buf, name)
 	} else {
+		var n string
+		if hasSpecials(name) {
+			n = encodeHeader(quotedprintable.B.NewHeaderEncoder(msg.charset), name)
+		} else {
+			n = encodeHeader(msg.hEncoder, name)
+		}
 		buf.WriteString(n)
 	}
 	buf.WriteString(" <")
@@ -295,6 +296,25 @@ func quote(buf *bytes.Buffer, text string) {
 	buf.WriteByte('"')
 }
 
+func hasSpecials(text string) bool {
+	for i := 0; i < len(text); i++ {
+		switch c := text[i]; c {
+		case '(', ')', '<', '>', '[', ']', ':', ';', '@', '\\', ',', '.', '"':
+			return true
+		}
+	}
+
+	return false
+}
+
+func encodeHeader(enc *quotedprintable.HeaderEncoder, value string) string {
+	if !quotedprintable.NeedsEncoding(value) {
+		return value
+	}
+
+	return enc.Encode(value)
+}
+
 var bufPool = sync.Pool{
 	New: func() interface{} {
 		return new(bytes.Buffer)

gomail_test.go

@@ -22,6 +22,7 @@ func TestMessage(t *testing.T) {
 	msg.SetAddressHeader("From", "from@example.com", "Señor From")
 	msg.SetHeader("To", msg.FormatAddress("to@example.com", "Señor To"), "tobis@example.com")
 	msg.SetAddressHeader("Cc", "cc@example.com", "A, B")
+	msg.SetAddressHeader("X-To", "ccbis@example.com", "à, b")
 	msg.SetDateHeader("X-Date", stubNow())
 	msg.SetHeader("X-Date-2", msg.FormatDate(stubNow()))
 	msg.SetHeader("Subject", "¡Hola, señor!")
@@ -40,6 +41,7 @@ func TestMessage(t *testing.T) {
 		content: "From: =?UTF-8?Q?Se=C3=B1or_From?= <from@example.com>\r\n" +
 			"To: =?UTF-8?Q?Se=C3=B1or_To?= <to@example.com>, tobis@example.com\r\n" +
 			"Cc: \"A, B\" <cc@example.com>\r\n" +
+			"X-To: =?UTF-8?B?w6AsIGI=?= <ccbis@example.com>\r\n" +
 			"X-Date: Wed, 25 Jun 2014 17:46:00 +0000\r\n" +
 			"X-Date-2: Wed, 25 Jun 2014 17:46:00 +0000\r\n" +
 			"X-Headers: Test, =?UTF-8?Q?Caf=C3=A9?=\r\n" +