* 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
This removes the stacking of type parameters that occurs when invoking
trait methods, and fixes all places in the standard library that were
relying on it. It is somewhat awkward in places; I think we'll probably
want something like the `Foo::<for T>::new()` syntax.
