Set unstable feature names appropriately

* `core` - for the core crate
* `hash` - hashing
* `io` - io
* `path` - path
* `alloc` - alloc crate
* `rand` - rand crate
* `collections` - collections crate
* `std_misc` - other parts of std
* `test` - test crate
* `rustc_private` - everything else

src/libstd/lib.rs

@@ -114,7 +114,13 @@
 #![feature(optin_builtin_traits)]
 #![feature(int_uint)]
 #![feature(int_uint)]
-#![feature(unnamed_feature)]
+#![feature(core)]
+#![feature(libc)]
+#![feature(alloc)]
+#![feature(unicode)]
+#![feature(collections)]
+#![feature(rand)]
+#![feature(hash)]
 
 // Don't link to std. We are std.
 #![no_std]