V3.9.2.3 bugfixes for --kwin; Set GID of video and audio to host GID
V3.9.2.3 bugfixes for --kwin; Set GID of video and audio to host GID

# 25.02.2018 V3.9.2.3   set container GID of video and audio to same as on host
#                       cat docker daemon messages for startup error message
# 24.02.2018            bugfix --kwin: kwin_wayland seems to need dbus-launch now
# 15.02.2018            mywatch(): replaced watch with custom sleep loop, watch failed in --hostdisplay (xinitrc) setups
# 10.02.2018            --exe: only forward stdin if not empty
#                       finish(): use pkill in most cases instead of kill to avoid kill success messages
#                       bugfix --weston/--kwin: wait for file creation of wayland socket, checking logfile is not enough
#                       mywatch(): verbose output
mviereck/x11docker