Available configuration file options:

• verbosity [integer] sets the verbosity level
• prefix_cond [expr] condition to recognize something as a prefix
• statistics-file [file] File to compute statistics on
• input-file [file] File to process
• mode [collector/filter] How the program should act.
• pass [1..3] How many times word should be examined. For filter mode only 1 and 2 are valid values.