Merge pull request #7095 from kaspar030/add_headerguard_check_script

boards/avsextrem/include/board.h

boards/calliope-mini/include/board.h

boards/chronos/include/board.h

boards/ek-lm4f120xl/include/board.h

boards/frdm-k64f/include/board.h

boards/microbit/include/board.h

boards/mips-malta/include/board.h

boards/mips-malta/include/periph_conf.h

boards/msb-430-common/drivers/include/sht11-board.h

boards/msb-430/include/board.h

boards/msb-430h/include/board.h

boards/msba2-common/drivers/include/sht11-board.h

boards/msba2-common/include/msba2_common.h

boards/msba2-common/tools/src/control_2xxx.h

boards/msba2-common/tools/src/lpc2k_pgm.h

boards/msba2-common/tools/src/serial.h

boards/mulle/include/periph_conf.h

boards/nrf51dongle/include/board.h

boards/nrf52840dk/include/board.h

boards/nrf52840dk/include/periph_conf.h