Failing test for unicode flub on response side

If a response body is unicode, we encode it using ASCII, which is pretty
much horrible. This is pressing now that all response bodies are unicode
as of #326.
Fix typo in test name
Clean up byte usage in test
Fix encoding when body is unicode; #254

If a Response body is a unicode we want to encode it using self.charset
when sending to the wire. For static resources the body should be a byte
string so we shouldn't need to encode it at all.
Merge pull request #334 from gittip/response-chokes-on-non-ascii

Response chokes on non ascii