In a stereo scenario, the listener will use a channel map of
{SIDE_LEFT, SIDE_RIGHT}, but sounds will default to
{FRONT_LEFT, FRONT_RIGHT}. As a result, channel mapping will be
performed to do the conversion. By instead defaulting stereo sounds
to be consistent with the listener, a passthrough path can be used
instead, improving efficiency.

fixed a little problem with changing devices when initialized our device config as duplex; fixed typos

The idea behind this is to avoid subtle bugs that are a result of
accidentally not using atomic operations to reference variables that
must always be used atomically.

This commit does not convert every atomic variable to the new system,
however going forward this will need to be adopted over time.

Public issue https://github.com/mackron/miniaudio/issues/572

Public issue https://github.com/mackron/miniaudio/issues/572

Public issue https://github.com/mackron/miniaudio/issues/572

Public issue https://github.com/mackron/miniaudio/issues/569

Issue from raylib: https://github.com/raysan5/raylib/issues/2118

This reverts commit 0788be81.

This change was technically incorrect. Reverting this change for now
until a better fix is in place. Likely this will require an extra
parameter for controlling this.