Move the `ioreg!` macro to `ioreg_old!`

Indentation alignment isn't corrected, but the `_old` suffix is ugly
anyway.
Merge pull request #127 from bharrisau/ioreg_rename

Move the `ioreg!` macro to `ioreg_old!`
Merge pull request #108 from bgamari/ioreg-rebased

Added new ioreg syntax extension