audiounit: Address issue #240 plus minor cleanups (#241)
audiounit: Address issue #240 plus minor cleanups (#241)

* audiounit: Replace hand-rolled fieldOffset with offsetof.

* audiounit: Replace PRINT_ERROR_CODE with LOG.

* audiounit: Avoid duplicating log messages where a format string can be used.

* audiounit: Whitespace cleanup.

kinetiknz/cubeb,kinetiknz/cubeb,kinetiknz/cubeb