Merge pull request #10148 from danpetry/driver_tsl4531x

drivers/Makefile.dep

drivers/Makefile.include

drivers/include/tsl4531x.h

drivers/tsl4531x/Makefile

drivers/tsl4531x/include/tsl4531x_internals.h

drivers/tsl4531x/include/tsl4531x_params.h

drivers/tsl4531x/tsl4531x.c

drivers/tsl4531x/tsl4531x_saul.c

sys/auto_init/auto_init.c

sys/auto_init/saul/auto_init_tsl4531x.c

tests/driver_tsl4531x/Makefile

tests/driver_tsl4531x/README.md

tests/driver_tsl4531x/main.c