char* getOptionValue(string option) called instead of bool getOption(string option)

[michischramm]

Going through the code, I wondered in the ligra.h file why the lines 475 - 478 call the function char* getOptionValue(string option) and not bool getOption(string option) and why this works. After a while I undestood this works because the last argument is always the file, thus after every option is always another argument. I don't think this is wanted, because the function bool getOption(string option) exists, too.