fix all sign-compare warnings

src/drivers/distance_sensor/mb12xx/CMakeLists.txt

src/drivers/distance_sensor/mb12xx/mb12xx.cpp

src/drivers/distance_sensor/sf0x/CMakeLists.txt

src/drivers/distance_sensor/sf0x/sf0x.cpp

src/drivers/distance_sensor/sf0x/sf0x_tests/CMakeLists.txt

src/drivers/distance_sensor/sf0x/sf0x_tests/SF0XTest.cpp

src/drivers/distance_sensor/sf1xx/CMakeLists.txt

src/drivers/distance_sensor/srf02/CMakeLists.txt

src/drivers/distance_sensor/teraranger/CMakeLists.txt

src/drivers/distance_sensor/teraranger/teraranger.cpp

src/drivers/distance_sensor/tfmini/CMakeLists.txt

src/drivers/distance_sensor/tfmini/tfmini.cpp

src/drivers/vmount/CMakeLists.txt

src/drivers/vmount/vmount.cpp

src/lib/controllib/BlockLowPassVector.hpp

src/modules/commander/CMakeLists.txt

src/modules/commander/accelerometer_calibration.cpp

src/modules/commander/calibration_routines.cpp

src/modules/commander/calibration_routines.h

src/modules/commander/commander.cpp