Introducing the CustomLangsAPI

More language files for everyone, in Javascript. Documentation coming soon.
Add Yuidoc documentation to PrefsAPI

Refactored PreferencesAPI's code and wrote a decent documentation. You can generate the HTML documentation with YUIDoc.
Add Yuidoc documentation to CustomLangsAPI

The documentation for both the APIs is now complete. It will be available online very soon.
Add localizations using CustomLangsAPI

Simple, fast and efficient. What's better? (using Google Translator is not fast unfortunately). By the way - also implemented a new method in CustomLangsAPI which is the perfect way to retrieve language strings without knowing the langfile name.