This change makes the current atlas feature (and additionally all
attributes of related child features) available to the source of
a composer HTML item, allowing the item to dynamically adjust
its rendered HTML in response to the feature's properties. An
example use case is dynamically populating a HTML table with
all the attributes of related child features for the atlas
feature.
To use this, the HTML source must implement a "setFeature(feature)"
JavaScript function. This function is called whenever the atlas
feature changes, and is passed the atlas feature (+related attributes)
as a GeoJSON Feature.
Sponsored by Kanton of Zug, Switzerland
