Add a test for sending unicode data in http headers
Borrow b() and u() from six
Use u() to be python 3.1 compatible
Accept bytestrings in tuples
Accept bytestrings in option values
Do the encode to latin1-decode to utf8 trick
Use a more appropriate message under Python 3
Do the encode-decode hack only on python 3, on python 2 decode as utf-8
Remove dependency on util