Move the serial module into a 'legacy' module

src/legacy/mod.rs

@@ -0,0 +1,9 @@
+//! Legacy code.
+//!
+//! The code in here needs to be cleaned up and rewritten.
+//!
+//! Once a replacement exists, these legacy modules may be removed
+//! in a major release!
+
+pub mod serial;
+

src/lib.rs

@@ -14,10 +14,10 @@
 #![no_std]
 
 pub use self::register::{Bitset, Mask, Register, RegisterValue};
-pub use self::pin::Pin;
+pub use self::pin::{DataDirection, Pin};
 
 pub mod prelude;
-pub mod serial;
+pub mod legacy;
 pub mod cores;
 pub mod modules;
 
@@ -28,8 +28,3 @@ mod pin;
 #[doc(hidden)]
 pub mod std_stub;
 
-pub enum DataDirection {
-    Input,
-    Output,
-}
-

src/pin.rs

@@ -1,4 +1,9 @@
-use {DataDirection, Register};
+use Register;
+
+pub enum DataDirection {
+    Input,
+    Output,
+}
 
 /// An IO pin.
 pub trait Pin {