Add static wrapper method to Jsonize class

Added static method to Jsonize class: `Jsonize::encode()` as alias for jsonizenc()
This makes use and installation slightly easier, because it no longer requires configuring and calling a useless Yii Application component only for the purpose of autoloading the library. 

Modified readme to match changes.

This should still be backwords compatible with the old `jsonizenc()` (as long as Yii component is added to the components array in main.php and preloaded or called before use), but it's use is no longer recommend. Instead call `Jsonize::encode()`

Pull this change if you like it. Close or ignore if unwanted.