mpd 0.18.16

Since 0.18.14, the following things have changed:
- fix a DSD breakage due to a typo in 0.18.15
- fix issue with large command lists
- fix of an old breakage of the MixRamp feature

Closes #32744.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
mpd: update 0.18.16 bottle.