Merge topic branch t/mixer into master

A few patches for the sleep subcommand of para_mixer, in particular
the two new options to set the initial mood.

This code has been cooking in next for exactly one month.

* refs/heads/t/mixer:
  mixer: sleep: Fade out before stopping the stream.
  mixer: sleep: Cycle audiod on stop.
  mixer: sleep: Add --initial-mood and --initial-delay.
  mixer: sleep: Always set initial volume and channel.
  mixer: sleep: Improve description of sleep subcommand.

diff --combined NEWS.md
index 45e46bc627a13398a24dbe9dc220beeeb657bed4,5a00175c3255702b03ec86e0af1938863f53ba4d..539f75768c6b99ef6bbbff4074e8fd309692b5c4
--- 1/NEWS.md
--- 2/NEWS.md
+++ b/NEWS.md
@@@ -1,15 -1,6 +1,18 @@@
  NEWS
  ====
  
 +------------------------------------------
 +0.7.2 (to be announced) "optical friction"
 +------------------------------------------
 +
++- The sleep subcommand of para_mixer gained two options to control
++  the startup mood and the time period before fade-out starts. A bunch
++  of further improvements for this subcommand went in as well.
 +- Minor cleanup of the net subsystem.
 +
 +Downloads:
 +[tarball](./releases/paraslash-git.tar.xz)
 +
  --------------------------------------
  0.7.1 (2022-10-03) "digital spindrift"
  --------------------------------------
@@@ -36,7 -27,6 +39,7 @@@ usual mix of bug fixes and minor improv
    requires support from the compiler, the oldest supported gcc version
    has been bumped to gcc-5.4 (released in 2015).
  
 +Downloads:
  [tarball](./releases/paraslash-0.7.1.tar.xz),
  [signature](./releases/paraslash-0.7.1.tar.xz.asc)
  
@@@ -229,23 -219,6 +232,23 @@@ Downloads
  [tarball](./releases/paraslash-0.6.1.tar.xz),
  [signature](./releases/paraslash-0.6.1.tar.xz.asc)
  
 +---------------------------------------
 +0.5.9 (2021-11-04) "reversed dimension"
 +---------------------------------------
 +This release contains a few important fixes which have accumulated in
 +the maint branch. The paraslash-0.5.x series has now reached its end
 +of life and will no longer be supported. All users should upgrade to
 +a more recent version at this point.
 +
 +- Fix an issue with the bash completion script.
 +- Initialize the random seed also when using libgrypt.
 +- Fix some compiler warnings in the resample filter
 +- Don't return spurious errors from the ff server command.
 +
 +Downloads:
 +[tarball](./releases/paraslash-0.5.9.tar.bz2),
 +[signature](./releases/paraslash-0.5.9.tar.bz2.asc)
 +
  ---------------------------------------
  0.5.8 (2017-09-23) "branching parabola"
  ---------------------------------------