Add enum variants to the type namespace

Change to resolve and update compiler and libs for uses.

[breaking-change]

Enum variants are now in both the value and type namespaces. This means that
if you have a variant with the same name as a type in scope in a module, you
will get a name clash and thus an error. The solution is to either rename the
type or the variant.

src/libsyntax/ext/base.rs

@@ -305,11 +305,11 @@ pub enum SyntaxExtension {
     /// based upon it.
     ///
     /// `#[deriving(...)]` is an `ItemDecorator`.
-    ItemDecorator(Box<ItemDecorator + 'static>),
+    Decorator(Box<ItemDecorator + 'static>),
 
     /// A syntax extension that is attached to an item and modifies it
     /// in-place.
-    ItemModifier(Box<ItemModifier + 'static>),
+    Modifier(Box<ItemModifier + 'static>),
 
     /// A normal, function-like syntax extension.
     ///
@@ -387,7 +387,7 @@ fn initial_syntax_expander_table() -> SyntaxEnv {
                             builtin_normal_expander(
                                     ext::log_syntax::expand_syntax_ext));
     syntax_expanders.insert(intern("deriving"),
-                            ItemDecorator(box ext::deriving::expand_meta_deriving));
+                            Decorator(box ext::deriving::expand_meta_deriving));
 
     // Quasi-quoting expanders
     syntax_expanders.insert(intern("quote_tokens"),