#### Proposal: To have `md-card` be a Directive instead of a Component so any element/component can be given Card behavior #### What is the expected behavior? To be able to have `<my-component mdCard>`. #### What is the current behavior? Currently only a `<md-card>` component can be visualized as a Card. #### What is the use-case or motivation for changing an existing behavior? Be able to apply whatever logic to `<my-component>` and still keep visualization like a Card with `mdCard` directive. #### Which versions of Angular, Material, OS, TypeScript, browsers are affected? All