webui, rest: Render UTF-8 addresses correctly, fixes #117

pkg/test/testdata/encodedheader.golden

@@ -0,0 +1,12 @@
+Mailbox: recipient
+From: X-äéß Y-äéß <fromuser@inbucket.org>
+To: [Test of ȇɲʢȯȡɪɴʛ <recipient@inbucket.org>]
+Subject: Test of ȇɲʢȯȡɪɴʛ
+Size: 351
+
+BODY TEXT:
+Basic message.
+
+
+BODY HTML:
+

pkg/test/testdata/encodedheader.txt

@@ -0,0 +1,5 @@
+From: =?utf-8?q?X-=C3=A4=C3=A9=C3=9F_Y-=C3=A4=C3=A9=C3=9F?= <fromuser@inbucket.org>
+To: =?utf-8?B?VGVzdCBvZiDIh8myyqLIr8ihyarJtMqb?= <recipient@inbucket.org>
+Subject: =?utf-8?b?VGVzdCBvZiDIh8myyqLIr8ihyarJtMqb?=
+
+Basic message.

pkg/test/testdata/fullname.golden

@@ -1,6 +1,6 @@
 Mailbox: recipient
-From: "From User" <fromuser@inbucket.org>
-To: ["Rec I. Pient" <recipient@inbucket.org>]
+From: From User <fromuser@inbucket.org>
+To: [Rec I. Pient <recipient@inbucket.org>]
 Subject: basic subject
 Size: 246