Added a test case for the set_cookie encoding issues.
Helped syntax checker with file encoding declarations.

PEP-263 states that "If a Unicode string with a coding declaration
is passed to compile(), a SyntaxError will be raised" (under
"Implementation"). However. compile() can deal with Unicode
strings, just without the declaration.
Django 1.4 and Python 2.6 compatibility for the set_cookie changes.