Added basic tests for stderr and stdout logging
Duplicate stderr to log, not only redirect + code cleaning
Proper udf checking in amount calculation script
Small bugfix if log file is not given
Bugfix, wrong arguments
contains-method for udf dictionary, fixes #17
Only calculate amount if there are any artifacts with correct units
Return correct unit inputs in qc_amount_calculations
Bugfix, return incorrect inputs, and shorter variable names.
no_prepend argument to qc_amount_calculation
Epp_logger, no logging before logging settings are done
Stderr logger classed as info, to avoid confusing logs