Blender Git Loki

Merge branch 'master' into temp-cocoa-scroll-acceleration-fix

Bring back pre 2.8 scrolling acceleration

Up until the 2.79 release, we'd use our own acceleration method for scrolling
on macOS. Since then we rely on macOS to do this for us, but turns out it does
a worse job, at least for our needs. This is an experiment to bring the old
behavior back.