@attributes to render an object of name => value to attributes

[zachleat]

<img @attributes>

<!-- same as: -->
<img @attributes="webc.attributes">

to render all public attributes inherited as webc.attributes via #104.

You can also render an object (note the parenthesis there to avoid parsing as a JS block + label.

<img @attributes="({ myKey: 1 })">

to render <img myKey="1">

[zachleat]

Shipping with WebC v0.9.0