test purposes

returns (expected) exit code

Added --url to allow URLs to be specified in the config file that way

go weird, had to remove this. I should use trio soon for all the *printf()
stuff as this is too broken

better complains if there are missing input files for a test case
explaced exit-calls with returns instead

added lots of comments
added -s for short output and made it possible to run specific test cases
from the command line