Move predefined lenses to a public `lens` module

This avoids having those predefined types, which are optional, be in the
middle of the core types.

examples/colormaterial_color.rs

@@ -2,7 +2,7 @@ use bevy::{
     prelude::*,
     sprite::{MaterialMesh2dBundle, Mesh2dHandle},
 };
-use bevy_tweening::*;
+use bevy_tweening::{lens::*, *};
 use std::time::Duration;
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {

examples/menu.rs

 use bevy::prelude::*;
 use bevy_inspector_egui::WorldInspectorPlugin;
-use bevy_tweening::*;
+use bevy_tweening::{lens::*, *};
 use std::time::Duration;
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {

examples/sequence.rs

 use bevy::prelude::*;
-use bevy_tweening::*;
+use bevy_tweening::{lens::*, *};
 use std::time::Duration;
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {

examples/sprite_color.rs

 use bevy::prelude::*;
-use bevy_tweening::*;
+use bevy_tweening::{lens::*, *};
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     App::default()

examples/transform_rotation.rs

 use bevy::prelude::*;
-use bevy_tweening::*;
+use bevy_tweening::{lens::*, *};
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     App::default()

examples/transform_translation.rs

 use bevy::prelude::*;
-use bevy_tweening::*;
+use bevy_tweening::{lens::*, *};
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     App::default()

examples/ui_position.rs

 use bevy::prelude::*;
-use bevy_tweening::*;
+use bevy_tweening::{lens::*, *};
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     App::default()

src/lens.rs

+//! Collection of predefined lenses for common Bevy components and assets.
+
 use bevy::prelude::*;
 
 /// A lens over a subset of a component.

src/lib.rs

@@ -112,14 +112,11 @@ use interpolation::Ease as IEase;
 pub use interpolation::EaseFunction;
 pub use interpolation::Lerp;
 
-mod lens;
+pub mod lens;
 mod plugin;
 mod tweenable;
 
-pub use lens::{
-    ColorMaterialColorLens, Lens, SpriteColorLens, TextColorLens, TransformPositionLens,
-    TransformRotationLens, TransformScaleLens, UiPositionLens,
-};
+pub use lens::Lens;
 pub use plugin::{asset_animator_system, component_animator_system, TweeningPlugin};
 pub use tweenable::{Delay, Sequence, Tracks, Tween, Tweenable};
 
@@ -377,7 +374,7 @@ impl<T: Asset> AssetAnimator<T> {
 
 #[cfg(test)]
 mod tests {
-    use super::*;
+    use super::{lens::*, *};
 
     /// Animator::new()
     #[test]

src/tweenable.rs

@@ -398,7 +398,7 @@ impl<T> Tweenable<T> for Delay {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::{TransformPositionLens, TransformRotationLens};
+    use crate::lens::*;
     use std::sync::{Arc, Mutex};
     use std::time::Duration;