PR goes to dev
Merge pull request #87 from Niols/master

Add Dockerfiles, modify unit test system, and add unit tests
Merge https://github.com/FreederTeam/Freeder
Clean headers + cron.php
Merge branch 'dev' of https://github.com/FreederTeam/Freeder
Add unit tests todo list
Add support for different test scripts
Use regex in cron.php
Merge branch 'dev' of https://github.com/FreederTeam/Freeder
Add test for (un)?register_crontask
Modify check.sh, send error messages to /dev/null
debug cron.php