Add features

src/io/mod.rs

@@ -1,10 +1,5 @@
 //! I/O functions
 
-#![feature(asm)]
-#![feature(const_fn)]
-#![feature(core_intrinsics)]
-#![no_std]
-
 pub use self::dma::*;
 pub use self::io::*;
 pub use self::mmio::*;

src/lib.rs

@@ -1,4 +1,6 @@
 #![feature(asm)]
+#![feature(const_fn)]
+#![feature(core_intrinsics)]
 #![no_std]
 
 pub use self::arch::*;