start working on Representable::Schema, which allows to define representers (and more) in modules, combine then and then when including "finalise" them.
move knowledge about how to build the inline representer into the includer.
make ::build_inline the only method in module/Decorator to create the inline representer. this is soon to be replaced as we'll use Schema everywhere.
add Representable::Schema, first draft, only one level :)
maybe we don't need Schema and can just use Representable.representable_attrs. The only problem is, how does a Decorator know when do create the Decorator instances for :extend?

the great thing is: everything is just a property, inline representers are _always_ modules (abstract) that then get included into Decorator classes (concrete). this saves ton of code.
got the two examples with Decorator + Modules.
add notes how i'm gonna introduce ::inherit! for the representer module/class itself. we then can control where to manifest modules.
::included now calls base.inherit!(self) to delegate the actual inheritance to the including Module/Decorator.
start to differentiate when inheriting or including.
implement inheritable wrap by simply using Config.
and now, we don't need to set representation_wrap twice, as it is properly inherited.
more CHANGES.
no need for Schema, i'm pretty sure it goes without this new concept.
only manifest inline representers, everything else is up to the user.
REMOVE Definition#options.
cleanup *::Collection.
introduce ForCollection which generates a collection representer for you.