arep: find repeating lines

usage: ... | arep [-min {n}] [-max {n}] [-ie {expr}] [-oe {expr}]
Parameters:
-min {n}: specifiy the minimum number of repetitions
-max {n}:       -"-    maximum        -"-
  (take into account that this mode has to store _every_ input string
   in the memory)
-ie {expr}: format the input (must result a string)
-oe {expr}: output formatting

Examples:
... | arep
  -> print each line that repeated at least one time

... | arep -min 10
  -> print lines that repeated at least ten times (min. 11 occurences)

... | arep -ie "strtok(line, ' ', 0)"
  -> the repetition base is the first token of the input line (but the
     whole line will be printed (the first one, the other lines can contain
     different values in the other tokens))

... | arep -oe "str_after(line, ':')"
  -> repeated lines are printed, but the result contain only the substring
     after the first colon