- always check with state machine before reboot/shutdown
- respect BOARD_HAS_POWER_CONTROL (shutdown from command, low battery, power button)
- px4_shutdown_request add optional delay and always execute from HPWORK
- px4_shutdown_request split out px4_reboot_request
- this is one of the last pieces of the system that still depend on DriverFramework
- add new SIM_GPS_NOISE_X parameter for optionally increasing the GPS noise multiplier (was previously a gpssim command line option)
- add SIM_x_BLOCK parameters to block sensor publication
- SIM_GPS_BLOCK
- SIM_ACCEL_BLOCK
- SIM_GYRO_BLOCK
- SIM_MAG_BLOCK
- SIM_BARO_BLOCK
- SIM_DPRES_BLOCK