WebKitGTK+ 2.1.91 released!

This is a development release leading toward 2.2 series.

Add a cancelled signal to WebKitAuthenticationRequest in WebKit2 GTK+ API.
Add support for building with Wayland as the target.
Fix issues with rtsp streams embedded on video tag not loading.
Fix the media player to not set the system volume to 100%.
Ensure volume slider value is 0 when audio is muted.
Make GStreamer source element thread-safe.
Adjust internal size on GStreamer source element when receiving data if necessary.
Disable accelerated compositing if the system doesn’t support it.
Fix rendering of input buttons text with recent gnome-themes-standard.
Fix the cursor rendering when the mouse is over an image document with recent versions of GTK+.
Fix a crash in some cases when context menu is shown.
Fix the build on GNU/Hurd.
Translation updates: Brazilian Portuguese, Spanish.

Thanks to all the contributors who made possible this release.