7 - Implement the Fallback class.
15 - Add a Root interface and derivate Page from Root.
16 - Make a Core Package with the core classes (Parser, Widget, Container,
18 - Make a Basic (or Generic?) Package with simple implementations of all
19 classes in Core Package.
20 - Make other more specific Packages (like Album) with other widgets.
23 - Remove include statement, replace it with Root 'use' attribute.
31 - Make a way to put all classes in a package together in a single file to
32 avoid overhead in require_once calls.