I removed the `static-method-test.rs` test because it was heavily based
on `BaseIter` and there are plenty of other more complex uses of static
methods anyway.
fail!() used to require owned strings but can handle static strings
now. Also, it can pass its arguments to fmt!() on its own, no need for
the caller to call fmt!() itself.
A struct (inc. tuple struct) can be annotated with #[packed], so that there
is no padding between its elements, like GCC's `__attribute__((packed))`.
Closes#1704
