Add the class TestUtil, that provides functions used in several unit
tests. For the moment, it contains two function:
- fill_file(), that creates and fills a test file.
- remove_file(), that deletes a test file.
- Add class Configuration, a stock for the configuration structure.
- Add class UserInterface, that handles the configuration input.
- Update owlps-positioning.cc (delete old stuff like configuration) and
delete owlps-positioning.hh: we now have a compilable executable.