Set up new directory structure

Makefile.dep

sys/net/destiny/Makefile

sys/net/destiny/socket.h

sys/net/destiny/tcp.c

sys/net/destiny/tcp.h

sys/net/destiny/tcp_hc.c

sys/net/destiny/tcp_hc.h

sys/net/destiny/tcp_timer.c

sys/net/destiny/udp.c

sys/net/destiny/udp.h

sys/net/net_help/Makefile

sys/net/rpl/etx_beaconing.c

sys/net/rpl/etx_beaconing.h

sys/net/rpl/rpl.c

sys/net/rpl/rpl.h

sys/net/rpl/rpl_structs.h

sys/net/sixlowpan/Makefile

sys/net/sixlowpan/border.c

sys/net/sixlowpan/border.h

sys/net/sixlowpan/bordermultiplex.c