implement deserialization, rename mk_mem_buffer() to mem_buffer()

src/libstd/serialization.rs

@@ -5,3 +5,8 @@ Deprecated in favor of core::serialization."];
 use core;
 import list::list;
 import ebml::writer;
+
+import core::serialization::{serializer,deserializer};
+
+export serializer;
+export deserializer;