The 28 failues with python2.6
(email.__version__ 4.0.2) are all with a difference in whitespace.
My idea is to just make the whitespace equal. Or to explicitely parse
all headers)

FAIL: testEnc01 (test.test_mailgw.MailgwTestCase)
From: ['roundup-admin@your.tracker.email.domain.example',
'=?utf-8?b?w6TDtsO8w4TDlsOcw58sIE1hcnk=?=\n
<issue_tracker@your.tracker.email.domain.example>'] !=
['roundup-admin@your.tracker.email.domain.example',
'=?utf-8?b?w6TDtsO8w4TDlsOcw58sIE1hcnk=?=\n\t<issue_tracker@your.tracker.email.domain.example>']
  Reply-To: ['Roundup issue tracker\n
<issue_tracker@your.tracker.email.domain.example>'] != ['Roundup issue
tracker\n\t<issue_tracker@your.tracker.email.domain.example>']

FAIL: testEncNonUTF8 (test.test_mailgw.MailgwTestCase)
Reply-To: ['Roundup issue tracker\n
<issue_tracker@your.tracker.email.domain.example>'] != ['Roundup issue
tracker\n\t<issue_tracker@your.tracker.email.domain.example>']

FAIL: testFollowup (test.test_mailgw.MailgwTestCase)
FAIL: testFollowupExplicitSubjectChange (test.test_mailgw.MailgwTestCase)
FAIL: testFollowupNoNosyAuthor (test.test_mailgw.MailgwTestCase)
FAIL: testFollowupNoNosyAuthorButCopy (test.test_mailgw.MailgwTestCase)
FAIL: testFollowupNoNosyAuthorNoCopy (test.test_mailgw.MailgwTestCase)
FAIL: testFollowupNoNosyRecipients (test.test_mailgw.MailgwTestCase)
FAIL: testFollowupNoSubjectChange (test.test_mailgw.MailgwTestCase)
FAIL: testFollowupNosyAuthor (test.test_mailgw.MailgwTestCase)
FAIL: testFollowupNosyAuthorAndCopy (test.test_mailgw.MailgwTestCase)
FAIL: testFollowupNosyAuthorNosyCopy (test.test_mailgw.MailgwTestCase)
FAIL: testFollowupNosyRecipients (test.test_mailgw.MailgwTestCase)
FAIL: testFollowupStupidQuoting (test.test_mailgw.MailgwTestCase)
FAIL: testFollowupTitleMatch (test.test_mailgw.MailgwTestCase)
FAIL: testMultipartCharsetLatin1AttachFile (test.test_mailgw.MailgwTestCase)
FAIL: testMultipartCharsetLatin1NoAttach (test.test_mailgw.MailgwTestCase)
FAIL: testMultipartCharsetUTF8AttachFile (test.test_mailgw.MailgwTestCase)
FAIL: testMultipartCharsetUTF8NoAttach (test.test_mailgw.MailgwTestCase)
FAIL: testMultipartEnc01 (test.test_mailgw.MailgwTestCase)
FAIL: testMultipartRFC822 (test.test_mailgw.MailgwTestCase)
FAIL: testNewIssueAuthMsg (test.test_mailgw.MailgwTestCase)
FAIL: testNewIssueNoAuthorEmail (test.test_mailgw.MailgwTestCase)
FAIL: testNewIssueNoAuthorInfo (test.test_mailgw.MailgwTestCase)
FAIL: testNosyGeneration (test.test_mailgw.MailgwTestCase)
FAIL: testPropertyChangeOnly (test.test_mailgw.MailgwTestCase)
FAIL: testSecurityMessagePermissionContent (test.test_mailgw.MailgwTestCase)
FAIL: testSimpleFollowup (test.test_mailgw.MailgwTestCase)
FAILED (failures=28)