Cairo 1.17.6 (snapshot)

I spy with my little eye… a Cairo snapshot!

First of all, many, many thanks to everyone who contributed to Cairo
during this development cycle. A special thank you goes to:

- Adrian Johnson
- Uli Schlachter

for their tireless efforts in ensuring that the lights are still on
in the Cairo project.

This snapshot sees the removal of the following backends and platform
support:

- Qt4
- BeOS
- OS/2
- DirectFB
- DRM
- Cogl
- OpenVG

Thanks to all past contributors for their work on them. If you were using
any of these backends then you will need to stick to Cairo 1.16.

To offset the removal of the backends above, Adrian Johnson landed the
DWrite font rendering backend on Windows.

There have been multiple improvements in the Quartz backend, courtesy of
John Ralls.

Tim-Philipp Müller has kept the Meson build in top shape.

This snapshot is going to be the **last** release of Cairo with the
Autotools build system. The Meson build has seen many improvements and
it is considerably easier to maintain and faster to build.