Encode to ascii only, how did I end up encoding to utf8?
Merge pull request #128 from p-push/encode-to-ascii-only

Encode to ascii only like the docs say
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
Now encoding fails
yes
Handle python 2