cc2538: Set __NVIC_PRIO_BITS to the correct value of 3.
core: moved `#include`s outside the `extern "C"` guards
drivers: add `extern "C"` to header files
Merge pull request #1848 from locicontrols/cc2538-nvic-prio-bits

cc2538: Set __NVIC_PRIO_BITS to the correct value of 3.
byteorder: silence warnings in clang
Merge pull request #1852 from authmillenon/byteorder-silence

byteorder: silence warnings in clang
ip: set solicited node address correctly
Merge pull request #1805 from BytesGalore/extern_C_in_headers_core_unguard_includes

core: moved `#include`s outside the `extern "C"` guards
Merge pull request #1807 from BytesGalore/extern_C_in_headers_drivers

drivers: add `extern "C"` to header files
Merge pull request #1853 from authmillenon/solicited-node-address-fix

ip: set solicited node address correctly
core: msg: introduce msg_try_send
core: adapt to msg_try_send
Merge pull request #1847 from kaspar030/msg_try_send

core: introduce msg_try_send
 core: make sched_runqueues static

 PR #1000 overlooked to rename `runqueues` into `sched_runqueues` in
 `sched.h`. This shows that the variable is not used outside of
 `sched.c`.

 As the list should not be accessed outside of the scheduler, so it
 can be `static`.
sys: lib: ringbuffer: introduce ringbuffer_get_free

This function returns the number of bytes available in the ringbuffer.
Merge pull request #1650 from kaspar030/ringbuffer_get_free

sys: lib: ringbuffer: introduce ringbuffer_get_free
dist: add Dockerfile for docker builder container
Merge pull request #1637 from kaspar030/docker

dist: add Dockerfile for docker builder container
Merge pull request #1816 from Kijewski/runqueues-name-fixup

 core: make sched_runqueues static
make: doc: clean up dist Makefile