3.0 cake time

This re-implements `Time` to be a subclass of `Carbon`. As a side effect, most methods in Time are not static anymore.

An important change is that Time uses now `IntlDateFormatter`, this is great news for me as it finally make this library work as I wanted. It will correctly output the preferred date format in the correct language for the `nice`, `timeAgoInWords` and `i18nFormat`.