Further cppcheck warnings removed

applications/gui/src/camera.cpp

applications/gui/src/camera.hpp

applications/gui/src/media_panel.hpp

applications/gui/src/screen.cpp

applications/gui/src/src_window.hpp

components/common/cpp/src/timer.cpp

components/rgbd-sources/src/calibrate.cpp

components/rgbd-sources/test/frame_unit.cpp