#6101: Add imageapi_optimize to make file. Fix version of advagg.
#6101: Variable exports.
#6101: amend update hook to also include imageapi_optimize.
#6101: Shrink default_logo image.
#6101: Shrink toolbar_arrow.
#6232: Change image_toolkit to imageapi_optimize.
Merge pull request #6247 from openscholar/6232-optimize_images

Optimize Images