cpu/stm32l1/vectors.c: fix model stm32l152ret6 -> stm32l152re

puts => LOG_INFO for the MSP430 startup message

pkg: heatshrink: don't copy Makefile.heatshrink, use directly

sys/fmt: add hex/bytes sequence converters

puts => LOG_INFO for the MSP430 startup message

- fmt_bytes_hex: converts an array of bytes to an array of hex bytes
- fmt_hex_bytes: convert an array of hex bytes to an array of bytes

doc: Fix 'must not'/'may not' wording

sys/net/loramac: various improvements

- add missing typedef enums
- add default device class parameter

arm bug minor cpu/stm32f1 Fixed wrong flash page sizes

native: call rtc_init from board_init

add board/nucleo32-l031 adc configuration

fs: add littlefs as a package

drivers/kw2xrf: finish ongoing transmission before sending next frame

boards: fix doxygen inconsistencies and typos

sys/xtimer: remove duplicat _xtimer_set declaration

can: fix fall through error

sys/event/timeout: add timeout_clear() function

pkg: fix build jerryscript on macOS

sys/net/loramac: add device class enum

slipdev: simplify and solidify byte-unstuffing