added 'using std::abs' in types.h to hopefully avoid Linux bug
added 'using std::abs' in types.h to hopefully avoid Linux bug

(cherry picked from commit af72c6466d75f267c64fb5c27da336d3bf1ae608)

IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense