Available since: Gideros 2016.04
Sets the thickness (width) of the outline, and optionnally set the amount of 'feather' effect.
thickness: (number) line thickness in sprite coordinates units
feather: (number) Sets the amount of 'feather' effect, i.e. the ratio of the line thickness that will be blurred with background. Values range from 0 (sharp edges) to 1. optional