Blender Git Loki

Annotations: Add Stabilization for draw tool

This patch adds the stabilizer feature of GP to the annotations.

It has a toggle to activate it "Use Stabilizer", and two properties to control the behaviour of the smooth effect (factor and radius).
You can also use shift at start or in the air to temporaly use this feature.

{F8518283}

Differential Revision: https://developer.blender.org/D7648