i think i prefer this style. it's not _technically_ as safe as it was
before, but i prefer the explicitness of it (and it results in a little
bit less nesting in system functions which is nice).
i don't much like the need for an explicit `unwrap()` call however
but that's the tradeoff!
rename the old "apply" to "apply_to_device". meh. naming is hard.
i expect that most of the time i'd want to use the "apply" method i'm
adding here that handles device locking internally, so that is why i've
chosen to let it be called "apply" and to rename the other one.
for queuing audio "commands" which is a much nicer way to interact
with the audio system in general in a more complex application, as this
lets you play audio in more of a "fire and forget" kind of way.
Rc<AudioBuffer> play methods provided as an alternative because
otherwise you end up with a somewhat gross double-copy of the audio
buffer being played. but i didn't want to necessarily force use of
Rc<AudioBuffer> just yet ... thus both versions of these methods are
provided.
Gered