Hi all,

It's my first time commenting on this issue tracker so bear with me if this looks naive.

For the `plistlib` package, from Apple's own manual[1], there's actually a third JSON format.

It'll be good to indicate that `plistlib` doesn't support JSON format in the what's new page and corresponding document page.

It takes me sometime before I realize `plistlib` in Python 3.3 doesn't support the so called binary property list format. So if the JSON format won't be supported in this Python version, it'll save someone's time by just reading the manual.

[1]: https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man1/plutil.1.html