x86: shutdown on LPM_POWERDOWN
make: OSX: don't fail for empty .a archives

Fixes issue #1333.
tests/Travis: run unittests on x86, too
Merge pull request #1252 from Kijewski/travis-x86

tests/Travis: run unittests on qemu-i386, too
Merge pull request #1334 from Kijewski/issue-1333

make: OSX: don't fail for empty .a archives
Changed RIOT/Makefile.include, Makefile.base, Makefile.cflags, and native/Makefile.include to compile C and C++ files.
added riot_and_cpp example
added sudo apt-get install g++-multilib to travis.yml
Merge pull request #981 from vanhieubk/nhat_mixCompiler

Another way to mix c and cpp in user app with RIOT [native]
bugfix: msp430 can write now more then one byte to flash
Merge pull request #1348 from SGSSGene/bugfix_writetorom

msp430: fix writing more than one byte to flash
pyterm: made python compatible with python2 and python3

In python 3 there is no implicit converion of bytes to str or character.
Merge pull request #1349 from cgundogan/fix_pyterm_python_version

pyterm: made python compatible with python2 and python3
Merge remote-tracking branch 'upstream/master' into cbor