boards/samr21-xpro: define serial port for OS X

6lowpan: do garbage collect unreachable NCEs

RFC6775 says "if NUD on the router determines that the host is UNREACHABLE (based on the logic in [RFC4861]), the NCE SHOULD NOT be deleted but rather retained until the Registration Lifetime expires." Since this is a "SHOULD NOT" and not a "MUST NOT", we can still remove these NCEs to circumvent NCEs going into UNREACHABLE and never leave this state again. Actually removing these entries from the cache seems also be the better choice for memory constraint device.

at86rf2xx: mask MSB in PHR for 802.15.4 compliance

cpu/k60: remove leftover files from old syscall implementation

socket_base: remove deprecated header files

oonf_api: adapt for new sockets

6lowpan: make SLAAC work

There's no real need for this flag, but it causes problem during address registration.

By adding a newly added prefix first, it is assured that the following router advertisement will already disseminate it via the PIO.

kinetis: timer: return error if timer channel is not zero.

drivers: add cc110x driver

6lowpan nd: PIO fixes

gnrc_sixlowpan_iphc: actually set context for unicast prefix based comp

Since the prefixes list stores pointers, one need to check for null pointers first.

While iterating over the prefixes the wrong upper limit was used for the for loop.

6lowpan IPHC: set stateful compression mode f. dst

For destionation addresses the stateful compression mode bit wasn't set.

shell_commands: provide command for 6Lo context administration at 6LBR

6lowpan: do not send NSs for new MC addresses

native/timer: fix return value for invalid channel

cpu: lpc2387: add spi_conf_pins()

gnrc_ipv6_netif: a RA source MUST be link-local	

nhdp: use conn instead of socket_base