Revert "Review and rebasing changes"

This reverts commit 6e0611a487.

src/libstd/os.rs

@@ -144,7 +144,7 @@ pub mod windows {
     use option::{None, Option};
     use option;
     use os::TMPBUF_SZ;
-    use slice::MutableSlice;
+    use slice::{MutableSlice, ImmutableSlice};
     use string::String;
     use str::StrSlice;
     use vec::Vec;