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/librustdoc/html/format.rs

@@ -277,7 +277,7 @@ fn path(w: &mut fmt::Formatter, path: &clean::Path, print_all: bool,
 }
 
 fn primitive_link(f: &mut fmt::Formatter,
-                  prim: clean::Primitive,
+                  prim: clean::PrimitiveType,
                   name: &str) -> fmt::Result {
     let m = cache_key.get().unwrap();
     let mut needs_termination = false;