Add palette dependency behind "colors" feature flag

Cargo.toml

@@ -24,6 +24,8 @@ debug = ["iced_winit/debug"]
 tokio = ["iced_futures/tokio"]
 # Enables `async-std` as the `executor::Default` on native platforms
 async-std = ["iced_futures/async-std"]
+# Enables advanced color conversion via `palette`
+colors = ["iced_core/colors"]
 
 [badges]
 maintenance = { status = "actively-developed" }
@@ -57,6 +59,7 @@ members = [
 ]
 
 [dependencies]
+iced_core = { version = "0.1", path = "core" }
 iced_futures = { version = "0.1", path = "futures" }
 
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies]

core/Cargo.toml

@@ -7,4 +7,11 @@ description = "The essential concepts of Iced"
 license = "MIT"
 repository = "https://github.com/hecrj/iced"
 
+[features]
+colors = ["palette"]
+
 [dependencies]
+
+[dependencies.palette]
+version = "0.5.0"
+optional = true