Fixed mixer chunk load and line ending detection for good.

src/modules/systemlib/mixer/mixer.cpp

src/modules/systemlib/mixer/mixer.h

src/modules/systemlib/mixer/mixer_group.cpp

src/modules/systemlib/mixer/mixer_load.c

src/modules/systemlib/mixer/mixer_load.h

src/modules/systemlib/mixer/mixer_multirotor.cpp

src/modules/systemlib/mixer/mixer_simple.cpp

src/systemcmds/mixer/mixer.cpp

src/systemcmds/tests/test_mixer.cpp