leet code replacement

[AndHager]

Closes #15

Improved leet code generation. Now it generates all 2^Count_Of_Replaceable_Chars -1 possible strings

[Nicicalu]

This works much better! Tahnk you, hope it gets merged sometime...

[AndreasInfo]

@AndHager Hi, it seems like they don't update the repo anymore. I started with some refactoring, cleaning and bug fixing on my own fork. If you are interested in keeping this project alive, too, you'll find the repo here: https://github.com/AndreasInfo/cupp2.