Changes since 0.4.0:
* Surface:
- Created derived classes for PDF, PS, SVG, Glitz,
X11 and Win32 surfaces, which are only available if your copy
of cairo supports those surfaces. The X11 and Win32 Surface headers
must be #included explicitly.
- Added write_to_png() and write_to_png_stream(), available when PNG
support is available in Cairo.
* Examples: Added PNG, PDF, PS, and SVG Surface examples.
* Added API documentation