Merge branch 'refs/heads/t/hash-sort-for-ls'

A single commit which allows to pass -s=h to the ls command for
sorting the output by hash value.

Cooking for six weeks.

* refs/heads/t/hash-sort-for-ls:
  server: Introduce hash sort for ls command.

diff --cc NEWS.md
index 5398d3a53a423716b0243a7543f9a3bbd15c1162,60b942389ffe1a7d71a61ced088965995548d416..894922f885ad14ac5c25f3f203706d5246889ad2
--- 1/NEWS.md
--- 2/NEWS.md
+++ b/NEWS.md
@@@ -1,16 -1,6 +1,18 @@@
  NEWS
  ====
  
- ------------------------------------------------
- 0.6.1 (to be announced) "hyperbolic correlation"
- ------------------------------------------------
++---------------------
++current master branch
++---------------------
 +
++- New sort order for the ls command: -s=h sorts the ls output by hash
++  value of the audio file.
 +- The contents of overview.pdf have been integrated into the user
 +  manual.
 +- The doxygen source browser has been disabled temporarily. The
 +  API reference is still online, though.
 +- Overhaul of the source code documentation.
 +
  -------------------------------
  0.6.0 (2017-04-28) "fuzzy flux"
  -------------------------------

diff --cc aft.c
Simple merge