Added automatic instancing of identical objects (#1775).
Added support for user attributes (#1775).
Added support for filter widths in output specifications (#1773).
Updated subdivision attributes to match Arnold versions 188.8.131.52 and onwards (#1775).
Moved path setup to wrapper. This means that
gaffer env kickcan be used to render a pregenerated ass file (#1774).
Updated public build to use OSL 1.7.2 and OIIO 1.6.14.
Protected internal TaskNode methods.
Replaced OSLRenderer with ShadingEngine.
Dropped support for OSL versions prior to 1.7.