Merge pull request #6628 from aabadie/nucleo_l053

boards/nucleo-l053/Makefile

boards/nucleo-l053/Makefile.dep

boards/nucleo-l053/Makefile.features

boards/nucleo-l053/Makefile.include

boards/nucleo-l053/board.c

boards/nucleo-l053/dist/openocd.cfg

boards/nucleo-l053/include/board.h

boards/nucleo-l053/include/periph_conf.h

cpu/stm32l0/include/cpu_conf.h

cpu/stm32l0/include/stm32l053xx.h

cpu/stm32l0/ldscripts/stm32l053r8.ld

examples/dtls-echo/Makefile

examples/emcute/Makefile

examples/gcoap/Makefile

examples/gnrc_border_router/Makefile

examples/gnrc_networking/Makefile

examples/gnrc_tftp/Makefile

examples/microcoap_server/Makefile

examples/nanocoap_server/Makefile

examples/posix_sockets/Makefile