Rationale:
1) It allows the callbacks to be set at initialization time which feels
a bit more intuitive to me.
2) It avoids the need to call mal_device_set_send_callback(), etc.
3) It's a bit more consistent with the onLog callback. Previously,
onLog would be passed to mal_device_init(), whereas onSend, etc were
set with mal_device_set_send_callback(), etc. which feels needlessly
inconsistent.
Rationale:
1) The number of parameters is just getting too much.
2) It makes it a bit easier to add new configuration properties in the
future. In particular, there's a chance there will be support added
for backend-specific properties.
David Reid