Use plone.app.imaging's quality setting if it exists
Use utility lookup to see if we have a custom scale
test that our scaling uses plone.app.imaging's quality setting, if it can be found
fix HISTORY
Require plone.app.imaging 1.0.8

...as 1.0.7 was released without the fix in https://github.com/plone/plone.app.imaging/pull/2
Merged quality branch