autotest: added unpack_mp.sh script

used to generated
http://firmware.diydrones.com/Tools/MissionPlanner/upgrade

Tools/scripts/unpack_mp.sh

@@ -0,0 +1,30 @@
+#!/bin/bash
+
+# unpack latest MissionPlanner*.zip on firmware.diydrones.com
+# to facilitate upgrade of existing MissionPlanner installs
+
+export PATH=$PATH:/bin:/usr/bin
+
+directory="$1"
+[ "$#" -eq 1 ] || {
+    echo "Usage: unpack_mp.sh <DIRECTORY>"
+    exit 1
+}
+cd $directory || exit 1
+
+mplatest=$(/bin/ls -tr MissionPlanner*zip | tail -1)
+lastsum="$(cat .latest 2> /dev/null)"
+[ "$lastsum" = "$(md5sum $mplatest)" ] && {
+    exit 0
+}
+
+echo "$(date) unpacking $mplatest"
+mkdir -p upgrade.new upgrade
+cd upgrade.new || exit 1
+unzip -q "../$mplatest"
+cd ..
+md5sum $mplatest > .latest
+mv upgrade upgrade.old
+mv upgrade.new upgrade
+rm -rf upgrade.old
+find upgrade -type f -print0 | xargs -i -0 md5sum '{}' > checksums.txt