cpu/nrf51822: fixed gpio driver
boards: added LED macro for pca1000 & yunjia-nrf
sys/net/ccn_lite/README.md change wording + add ACM ICN reference

sys/net/ccn_lite/README.md fix encoding
core: Provide functions for different byte orders

Rationale: see #1586.
tests: Add unittests for byteorder.h
tests: fix bad copy+paste in tests-core.h
Copy some files from cpu/sam3x8e to cpu/cc2538.
Add the latest cc2538-bsl script from https://github.com/JelmerT/cc2538-bsl/commit/f3701a0
boards/iot-lab_M3: change to openocd's new ftdi interface

Openocd communication was done over a deprecated interface definition,
namely ft2232. Using the new ftdi interface speeds up flashing and
doesn't throw warnings anymore.
c++: core: add extern C in header files
Merge pull request #1779 from thomaseichinger/stm32f1-flashing

boards/iot-lab_M3: change to openocd's new ftdi interface
stm32f1: implement RTT driver
Merge pull request #1613 from thomaseichinger/stm32f1_rtt

stm32f1:iot-lab_M3: implement RTT driver
sixlowpan: fix ipv6_addr_init_prefix
Merge pull request #1781 from authmillenon/sixlowpan-fix-prefix-init

sixlowpan: fix ipv6_addr_init_prefix
Merge pull request #1783 from dangnhat/extern_C_in_headers_core

c++: core: add extern C in header files
Merge pull request #1699 from Kijewski/issue-1586

core: Provide functions for different byte orders
at86rf231: replace vtimer_usleep by hwtimer_wait

This fixes a bug where the callback to unlock the thread, put to sleep by
`vtimer_usleep` wouldn't be woken up due to overhead. Using hwtimer_wait
works for now, but this section will be replaced a driver refactor anyway.
cpu/stm32f1:board/iot-lab_M3: fix and cleanup for GPIO low level driver
cpu/stm32f1: overwrite HWTIMER_WAIT_OVERHEAD