x86: shutdown on LPM_POWERDOWN
drivers: added set_absolute to timer interface
Merge pull request #1289 from haukepetersen/fix_drivers_periph_timer

drivers: added set_absolute to timer interface
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
Merge branch 'nhat_mixCompiler' into nhat_mixCompiler2
added sudo apt-get install g++ to travis.yml