Prep gcore splitup: move various symbols into their own modules (#2746)

* move `trait AsU32` from `gcore::vector::misc` to `gcore`

* move blending and gradient to their own modules

* fix unused warnings

* move `Quad`, `Rect` and `BBox` to `gcore::math`

* extract `ReferencePoint` and transform nodes from `transform`

* move color-related code to `mod color`

* fix unused warning in test code

* move blending-related nodes and code to `mod blending_nodes`

* move ClickTarget code to `mod vector::click_target`

node-graph/gcore/src/lib.rs

@@ -1,38 +1,40 @@
 #[macro_use]
 extern crate log;
 
-pub use crate as graphene_core;
-pub use ctor;
-pub use num_traits;
-
 pub mod animation;
+pub mod blending;
+pub mod blending_nodes;
+pub mod color;
 pub mod consts;
 pub mod context;
 pub mod generic;
+pub mod gradient;
+mod graphic_element;
 pub mod instances;
 pub mod logic;
+pub mod math;
+pub mod memo;
 pub mod misc;
 pub mod ops;
+pub mod raster;
 pub mod raster_types;
+pub mod registry;
 pub mod structural;
 pub mod text;
+pub mod transform;
+pub mod transform_nodes;
 pub mod uuid;
 pub mod value;
-
-pub mod memo;
-
-pub mod raster;
-pub mod transform;
-
-mod graphic_element;
-pub use graphic_element::*;
 pub mod vector;
 
-pub mod registry;
-
+pub use crate as graphene_core;
+pub use blending::*;
 pub use context::*;
+pub use ctor;
 pub use dyn_any::{StaticTypeSized, WasmNotSend, WasmNotSync};
+pub use graphic_element::*;
 pub use memo::MemoHash;
+pub use num_traits;
 pub use raster::Color;
 use std::any::TypeId;
 use std::future::Future;
@@ -159,3 +161,12 @@ pub trait NodeInputDecleration {
 	fn identifier() -> &'static str;
 	type Result;
 }
+
+pub trait AsU32 {
+	fn as_u32(&self) -> u32;
+}
+impl AsU32 for u32 {
+	fn as_u32(&self) -> u32 {
+		*self
+	}
+}