moved boards into subdirectory

boards/native/drivers/native-uart0.c

boards/native/include/board.h

boards/native/include/board_internal.h

boards/olimex_lpc2148/board_init.c

boards/olimex_lpc2148/debug_uart.c

boards/olimex_lpc2148/include/board.h

boards/olimex_lpc2148/include/rs232.h

boards/olimex_lpc2148/rs232.c

boards/olimex_lpc2148/tick.c

boards/olimex_lpc2148/tools/lpc2148_flash.gdb

boards/pttu/board_init.c

boards/pttu/include/board.h

boards/pttu/tools/jtag.txt

boards/pttu/tools/olimex-arm-usb-ocd.cfg

boards/pttu/tools/openocd-pttu.cfg

boards/pttu/tools/openocd-pttu.sh

boards/pttu/tools/pttu_debug.gdb

boards/redbee-econotag/Makefile

boards/redbee-econotag/Makefile.dep

boards/redbee-econotag/Makefile.include