Motion animation export: a study or a joint drive as an animated GIF (#1680)

Thanks @SychPL.

crates/render/src/lib.rs

@@ -8,6 +8,7 @@ mod analysis;
 mod backend;
 mod camera;
 mod curve_display;
+mod gif;
 pub mod job;
 pub mod lighting;
 mod product;
@@ -28,6 +29,7 @@ pub use backend::{
 };
 pub use camera::{Camera, CameraAnim, Mat4, Quat, StandardView, UpAxis, ease_in_out};
 pub use curve_display::{PixelCurveView, SampledPath, SamplingBudget, SamplingQuality, sample_segment, sample_segment_unclipped};
+pub use gif::gif;
 pub use product::{FaceAppearance, ProductMesh, ProductScene};
 pub use raster::{Canvas, render, render_png, render_transparent};
 pub use scene::{Rgb, SECTION_CAP, Scene, SceneLine, SceneMesh, png};