PC-Lint warnings fixed:

PC-Lint warnings fixed:
- Info 1786: Implicit conversion to Boolean (return) (int to bool);
- Info 1705: static class members may be accessed by the scoping operator;
- Info 713: Loss of precision (arg. no. 2) (unsigned int to int);
- Info 737: Loss of sign in promotion from int to unsigned int in statement 'size -= sizeof(word_array[ 0 ])';
- Info 713: Loss of precision (assignment) (unsigned int to int) in statement 'size -= sizeof(word_array[ 0 ])';
- Info 1773: Attempt to cast away const (or volatile) in statement 'cksum += *(uint8_t*) word_array';
- Replaced all C-style casts by C++ style casts.