WebKitGTK 2.53.1 released!

This is the first development release leading toward 2.54 series.

Remove the option to use cairo for 2D rendering.
Implement GPU atlas creation and replay substitution for batched raster image uploads.
Improved non accelerated composited mode by using the same buffer sharing implementation as accelerated mode.
The on-demand hardware acceleration policy is now deprecated in GTK3 API.
Add new improved API for page favicons.
Add webkit_feature_list_find() to public API.
Support PGO features in regular CMake builds.
Fix several crashes and rendering issues.

Thanks to all the contributors who made possible this release.