rustuv: Get all tests passing again after refactor

All tests except for the homing tests are now working again with the
librustuv/libgreen refactoring. The homing-related tests are currently commented
out and now placed in the rustuv::homing module.

I plan on refactoring scheduler pool spawning in order to enable more homing
tests in a future commit.

src/libstd/io/mod.rs

@@ -313,9 +313,8 @@ pub use self::net::udp::UdpStream;
 pub use self::pipe::PipeStream;
 pub use self::process::Process;
 
-/// Testing helpers
-#[cfg(test)]
-mod test;
+/// Various utility functions useful for writing I/O tests
+pub mod test;
 
 /// Synchronous, non-blocking filesystem operations.
 pub mod fs;