Merge pull request #8061 from haukepetersen/opt_boards_wsn430

boards/common/wsn430/Makefile.features

boards/common/wsn430/Makefile.include

boards/common/wsn430/board_init.c

boards/common/wsn430/include/board.h

boards/common/wsn430/include/periph_conf.h

boards/wsn430-v1_3b/Makefile

boards/wsn430-v1_3b/Makefile.features

boards/wsn430-v1_3b/Makefile.include

boards/wsn430-v1_3b/include/board.h

boards/wsn430-v1_4/Makefile

boards/wsn430-v1_4/Makefile.features

boards/wsn430-v1_4/Makefile.include

boards/wsn430-v1_4/include/board.h