Add raw_entry and tests from libstd

Fixes #23

Author: Amanieu

src/lib.rs

@@ -12,10 +12,24 @@
 #![no_std]
 #![cfg_attr(
     feature = "nightly",
-    feature(alloc, alloc_layout_extra, allocator_api, ptr_offset_from, test, core_intrinsics)
+    feature(
+        alloc,
+        alloc_layout_extra,
+        allocator_api,
+        ptr_offset_from,
+        test,
+        core_intrinsics,
+        dropck_eyepatch
+    )
 )]
 #![warn(missing_docs)]
 
+#[cfg(test)]
+#[macro_use]
+extern crate std;
+#[cfg(test)]
+extern crate rand;
+
 #[cfg(feature = "nightly")]
 extern crate alloc;
 extern crate byteorder;