quad: use normalized pwm value throughout app

quad/src/quad_app/util.c

quad/src/quad_app/util.h

quad/src/virt_quad/hw_impl_unix.c

quad/src/virt_quad/hw_impl_unix.h

quad/src/virt_quad/hw_impl_unix_motor.c

quad/src/virt_quad/hw_impl_unix_rc_receiver.c

quad/src/virt_quad/main.c

quad/xsdk_workspace/real_quad/src/hw_impl_zybo.c

quad/xsdk_workspace/real_quad/src/hw_impl_zybo.h

quad/xsdk_workspace/real_quad/src/hw_impl_zybo_motor.c

quad/xsdk_workspace/real_quad/src/hw_impl_zybo_rc_receiver.c

quad/xsdk_workspace/real_quad/src/hw_impl_zybo_tests.c

quad/xsdk_workspace/real_quad/src/main.c