Revert ini-style config file implementation
    
    This reverts last two commits:
    759324f Correct all issues mentioned in the review.
    15eacf7 Allow to specify default args in a config file.
    
    A different approach was decided in #38.
    
    Related: https://pagure.io/fedora-easy-karma/issue/38
    Related: https://pagure.io/fedora-easy-karma/pull-request/52