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

dumps more information in case curl doesn't return success

since it has to survive http struct deletion