Merge pull request #341 from untitaker/sprint-branch

More v2
secret_key should be bytes
convert secret_key to bytes on 3.x as well
Use base64.b64encode in SecureCookie.quote
Use assert_equal(a, b) instead of assert a == b
Port SecureCookie.serialize to 3.x
Added a tox-test command
Make bytes comparable with safe_str_cmp
Give to_native default encoding as default charset
Fix bytes repr issue in SecureCookie.serialize
Port SecureCookie.unserialize to 3.x
Merge branch 'secure-cookie' into sprint-branch
test_base_request response['data'] should be bytes
bytes and unicode support is expected here

These tests should probably be tested on unicode and bytes explicitly
and not just by accident through testing on native strings.
Now this is way easier