Merge pull request #10065 from kYc0o/pr/riotboot

Makefile.dep

Makefile.include

boards/common/iotlab/Makefile.features

boards/nucleo-l152re/Makefile.features

boards/saml21-xpro/Makefile.features

boards/samr21-xpro/Makefile.features

bootloaders/riotboot/Makefile

bootloaders/riotboot/README.md

bootloaders/riotboot/main.c

cpu/cortexm_common/Makefile.include

cpu/cortexm_common/include/cpu.h

dist/tools/riotboot_gen_hdr/Makefile

dist/tools/riotboot_gen_hdr/common.c

dist/tools/riotboot_gen_hdr/common.h

dist/tools/riotboot_gen_hdr/genhdr.c

dist/tools/riotboot_gen_hdr/main.c

makefiles/boot/riotboot.mk

sys/include/riotboot/slot.h

sys/riotboot/Makefile

sys/riotboot/slot.c