add oonf_api pkg
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.
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.
Add test if the message queue is fair
posix: move posix semaphore in posix module
rename test for posix semaphore
correct copyright and doxygen
initial implementaion of dynamic routing information base