add oonf_api pkg
moved debugging statements from header to c file

Additionally, declaring the stacks as static.
amendment - to be squashed
tests: add test that shows sequence of received messages
test_thread_msg_seq: add missing main() return statement
core:mutex: allow idle thread to use mutexes
Add test if the message queue is fair
Change reboot signature.

Change from `void reboot(void)` to `int reboot(int mode)`.
Move reboot definition to core, rename architecture implementations
from reboot to reboot_arch.
Declare reboot mode(s) in kernel.h, reboot_arch in kernel_internal.h
Currently only one reboot mode is handled, its use is enforced.

Rationale:
A reboot function is already defined in <unistd.h> on BSD systems.
(See: http://www.openbsd.org/cgi-bin/man.cgi?query=reboot&sektion=2)
This patch not only allows native to build sensibly on these systems
but also streamlines RIOTs compatability with existing software.
shell: accept UTF8 input
shell: don't ignore IO errors
shell: add myself to authors
notify lowpan_transfer when IP packet is not routable

The IP process silently discarded an unroutable packet without replying to the 6LoWPAN layer, causing that thread to starve.
make: don't ignore failures in for loops

Add `|| exit 1` to all constructs like `@for i in $(DIRS) ; do "$(MAKE)" -C $$i ; done ;`, so that compilation stops on the first error.
Merge pull request #880 from LudwigOrtmann/live_fast_die_young

make: don't ignore failures in for loops
Ensure that stack pointer is correctly aligned during thread creation on MSP430
Merge pull request #630 from benpicco/oonf_api

[RFC] add oonf_api to pkg
Merge pull request #878 from OlegHahm/unroutable

net: sixlowpan: notify lowpan_transfer when IP packet is not routable
Merge pull request #822 from LudwigOrtmann/reboot_signature

core: change reboot signature.
ipc_pingpong: start receiving thread immediately

Rationale: When using `msg_send_receive()` the receiving thread needs to
be already in receiving mode.
posix: move posix semaphore in posix module