Commit submodules in preparation for 1.9.4

Signed-off-by: Thomas Braun <thomas.braun@byte-physics.de>
Prepare Release Notes for 1.9.4

Signed-off-by: Thomas Braun <thomas.braun@byte-physics.de>
download-stats: look for 1.9.4 now

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>