Start 0.5 release notes

RELEASES.txt

@@ -1,3 +1,39 @@
+Version 0.5 (December 2012)
+---------------------------
+
+   * ~700 changes, numerous bugfixes
+
+   * Language
+      * Traits may inherit from other traits
+      * Traits may declare default methods for the impls to use
+      * More support for explicit self arguments in methods - `self`, `&self`
+        `@self`, and `~self` all generally work as expected
+      * Static methods improved to work in more situations
+      * Completed the transition from the `#fmt` extension syntax to `fmt!`
+      * Removed old fixed length vector syntax - `[T]/N`
+      * Item macros
+      * Remove `<-` move operator
+      * Tuple structs - `struct Foo(Bar, Baz)`. Will replace newtype enums.
+      * Eq impls can be derived with #[deriving_eq]
+      * IterBytes impls can be derived with #[deriving_iter_bytes]
+      * Destructors can be added to all nominal types with the Drop trait
+      * Removed the special crate language for .rc files
+      * New token-based quasi-quoter, `quote!`
+      * More things can be constants now, including structs and
+        nullary enum variants
+
+   * Libraries
+      * New condition handling system in core::condition
+      * Timsort added to std::sort
+      * Serialization overhauled to be trait-based
+      * Expanded getopts definitions
+      * Moved futures to std
+      * More functions are pure now
+
+   * Tools
+      * Added a new, but still immature, REPL, rusti
+      * rustdoc and cargo are libraries now
+
 Version 0.4 (October 2012)
 --------------------------