sys/nhdp: Add interface-specific sequence number to created RFC5444 packets

[RFC] ng_ipv6_addr: add (optional) string conversion functions

ng_nomac: add to sys/Makefile

Documentation and example cleanup

Added cpuid_get for STM boards

The radio stack in default examples uses printf() and thus needs more
stack.

vtimer was changed in 6ee5e737 to use a
user specified type for vtimer_set_msg(), but documentation didn't
reflect this new API.

Per default, doxygen will take only the part until the first dot into
account for the brief description. In this case this leads to an
ambiguous overview over the IPC send functions.

net: added ng_nomac MAC implementation

Updating the README.md for examples/default

sys/nhdp: Allocate memory for NHDP's if table static

net: initial import of ethertypes and the ethernet header

Remove RPL warning removal in rpl_udp example

-Replaced date by rtc in examples/default/README.md as date is part of rtc.

boards/msbiot: Extend the provided features

boards/msbiot: Switch from st-util to openocd

sys: Set Local bit in EUI64 generated from CPU ID

Changed description for fd_t::fd in sys/include/fd.h

-Fixes  #1759
-Changes fd_t::__active to fd_t::internal_active
-Changes fd_t::fd to fd_t::internal_fd
-Made changes in the associated files that use the above fields.

-Fixes small typo error.

Reducing the scope of variable after running static code analyser.

cpu/kinetis_common: Enable UART hardware FIFO buffers.

sys/shell: added (ng_)netif shell commands