Support for theming in PHP templates has been dropped.
True theming should support theme inheritance, e.g. mytheme <- table <- default.
Currently, the Templating component does not support such inheritance. As the
only purpose of the themes so far was to style field groups with tables or
divs, and because automatic rendering of field groups/forms through the render()
method is discouraged and only recommended for rapid prototyping, themes are
dropped for now.
Fields can now easier support different data types in their underlying object.
These datatypes can be normalized to a single datatype using a normalization
transformer. The normalized value can then be transformed to the user's
representation with the value transformer (better name required?).