Log Message:
Update to 0.0.4

Changelog:
librevenge 0.0.4

- Fix possible crash in raw generators for unbalanced open/close calls.
- Fix build in C++11 mode.
- Fix gdb pretty printers and make them compatible with Python 3.
- Fix RVNGString::Iter::last(), which only worked correctly for strings
  containing only ASCII characters.
- Document the difference between RVNGString::len() and RVNGString::size().
- Considerably improve performance of RVNGString iterator (a crude
  measurement shows at least 45% improvement).