1) for parameters use references to CString instead of pointers to
buffers;
2) when returning strings use CString instead of pointer to char buffer
which caller needs to deallocate;
3) use BString even more.
1) classes CString and BString now have no memory overhead compared to
C-style null-terminated strings and character arrays respectively.
2) class StringBuilder is back and should be used when often Append’s
are needed.
