Fix jmavsim (#4)

* Install jMAVSim dependencies

* Restore jMAVSim desktop shortcut

* Try running jmavsim on validation

assets/desktop/jMAVSim.desktop

@@ -0,0 +1,10 @@
+[Desktop Entry]
+Version=1.0
+Type=Application
+Name=jMAVSim
+Comment=A lightweight PX4 simulator
+Exec=/bin/bash -c 'cd ~/PX4-Autopilot; make px4_sitl jmavsim'
+Icon=openjdk-8
+Path=
+Terminal=true
+StartupNotify=false

scripts/install_software.sh

@@ -35,6 +35,7 @@ git clone --recursive --depth 1 --branch v1.12.0 https://github.com/PX4/PX4-Auto
 # PX4 v1.11.1 script will happily run sudo by itself
 ${HOME}/PX4-Autopilot/Tools/setup/ubuntu.sh
 # Ubuntu 20.04 no longer sets assistive_technologies, thankfully
+sudo -E sh -c 'apt-get install -y ant openjdk-11-jdk' # Additional packages for jMAVSim
 
 echo "--- Prebuilding PX4 SITL configuration"
 make -C ${HOME}/PX4-Autopilot px4_sitl
@@ -202,3 +203,7 @@ rosversion nodelet
 
 echo "Trying running the Gazebo simulator, check the output"
 timeout --preserve-status 30 roslaunch clover_simulation simulator.launch gui:=false --screen
+
+echo "Trying running jMAVSim, check the output"
+cd ~/PX4-Autopilot
+HEADLESS=1 timeout --preserve-status 30 make px4_sitl jmavsim