More email package fixes.

This repairs the linear whitespace insertion between RFC 2047 encoded words
without leaving bogus trailing spaces at the end lines that end in encoded
words.

Current status: 7F/9E
diff --git a/Lib/email/test/test_email.py b/Lib/email/test/test_email.py
index 324332b..ef11e17 100644
--- a/Lib/email/test/test_email.py
+++ b/Lib/email/test/test_email.py
@@ -1556,7 +1556,7 @@
         header = make_header(dh)
         eq(str(header),
            'Re: r\xe4ksm\xf6rg\xe5s baz foo bar r\xe4ksm\xf6rg\xe5s')
-        self.ndiffAssertEqual(header.encode(), """\
+        self.ndiffAssertEqual(header.encode(maxlinelen=76), """\
 Re: =?mac-iceland?q?r=8Aksm=9Arg=8Cs?= baz foo bar =?mac-iceland?q?r=8Aksm?=
  =?mac-iceland?q?=9Arg=8Cs?=""")