Proper ctrl+c handling in Windows (fix #508)

src/ctrlc/mod.rs

@@ -1,11 +1,13 @@
-//! Provides handling for process interruption.
-//! There's no actual handling for Windows at the moment.
+mod interrupted;
+
 #[cfg(unix)]
 mod unix;
 #[cfg(unix)]
-pub use self::unix::*;
+pub use self::unix::set_handler;
 
 #[cfg(windows)]
 mod windows;
 #[cfg(windows)]
-pub use self::windows::*;
+pub use self::windows::set_handler;
+
+pub use self::interrupted::*;