Touch up and rebase previous commits

* Added `// no-pretty-expanded` to pretty-print a test, but not run it through
  the `expanded` variant.
* Removed #[deriving] and other expanded attributes after they are expanded
* Removed hacks around &str and &&str and friends (from both the parser and the
  pretty printer).
* Un-ignored a bunch of tests

src/libsyntax/parse/parser.rs

@@ -2241,9 +2241,6 @@ impl<'a> Parser<'a> {
               ExprVec(..) if m == MutImmutable => {
                 ExprVstore(e, ExprVstoreSlice)
               }
-              ExprLit(lit) if lit_is_str(lit) && m == MutImmutable => {
-                ExprVstore(e, ExprVstoreSlice)
-              }
               ExprVec(..) if m == MutMutable => {
                 ExprVstore(e, ExprVstoreMutSlice)
               }