Allow two digit versions

We currently throw an exception (and let PeTrack crash!), when a verion number has more than one digit:

        if(version1[i].length() == 1 && version1[i][0].isDigit())
        {
            version1_digits.push_back(version1[i].toInt());
        }
        else
        {
            throw std::invalid_argument("Invalid Input String!");
        }

We shouldn't do that. We already had versions (e.g. 8.15), with more than one digit in the minor version.