Merge pull request #749 from DonLakeFlyer/ArmDisarm

src/modules/commander/commander.cpp

src/modules/commander/commander_tests/commander_tests.cpp

...s/commander/commander_tests/state_machine_helper_test.cpp

...les/commander/commander_tests/state_machine_helper_test.h

src/modules/commander/state_machine_helper.cpp

src/modules/commander/state_machine_helper.h

src/modules/uORB/topics/vehicle_status.h

src/modules/unit_test/unit_test.cpp

src/modules/unit_test/unit_test.h