added examples/ipv6/http-server/
enable SLIP support for iotlab-* border-router
added print_local_addresses() in rpl-border-router init (tunslip6 should print ip addr)
removed unused var in border-router.c
fixed platform/iotlab-* warning: include dev/slip.h as needed
simplified examples/ipv6/http-server.c
fixed extra ')' in examples/ipv6/http-server.c
added preferend parent info in ipv6/http-server
trimmed includes for ipv6/http-server
fixed missing include for ipv6/http-server
fixup links in http-server.c