A bunch of changes, looks mainly like bug fixes and code cleanup.
Notable changes:
- `cubeb_get_min_latency`'s signature was changed to take params via
pointer, requiring Dolphin code to be tweaked in two places.
- A fix for kinetiknz/cubeb#320, as reported by @shuffle2
- Fixed build on FreeBSD (kinetiknz/cubeb#344), as contributed by @endrift