- new modules/simulation directory to collect all simulators and related modules
- new Tools/simulation directory to collect and organize scattered simulation submodules, scripts, etc
- simulation module renamed to simulator_mavlink
- sih renamed to simulator_sih (not a great name, but I wanted to be clear it was a simulator)
- ignition_simulator renamed to simulator_ignition_bridge
- large sitl_target.cmake split by simulation option and in some cases pushed to appropriate modules
- sitl targets broken down to what's actually available (eg jmavsim only has 1 model and 1 world)
- new Gazebo consistently referred to as Ignition for now (probably the least confusing thing until we fully drop Gazebo classic support someday)
This adds the env option PX4_FUZZ which runs the LLVM libFuzzer which
throws random bytes at mavlink_receiver using MAVLink messages over UDP.
The MAVLink messages that are being sent are valid, so the CRC is
calculated but the payload and msgid, etc. are generally garbage, unless
the fuzzing gets a msgid right by chance.
As I understand it, libFuzzer watches the test coverage and will try to
execute as much of the code as possible.