v0.13.0

• Support for .init_array/.fini_array processing is now optional;
  it's enabled by default, or by the "init-fini-arrays" feature.

• A new "tiny" example has been added showing techniques for producing
  very small executables.

• Origin no longer defines __dso_handle; that's now the job of C-ABI
  implementations such as mustang.

• The main function that origin calls has been renamed to origin_main,
  changed from extern "C" to extern "Rust", and the signature has
  changed to:

#[no_mangle]
fn origin_main(argc: usize, argv: *mut *mut u8, envp: *mut *mut u8) -> i32