#73: Path service for posix.
CAROLINE-9: Add path service. Add singleton. Add at exit manager.
CAROLINE-9: Rewrite camera calibration unit test.
CAROLINE-9: Add gmock checkout to the .travis.yml.
Merge pull request #89 from it-workshop/wp/CAROLINE-9/1

Wp/caroline 9/1
CAROLINE-27: Fix authors comments.
CAROLINE-27: Edit readme.