WebKitGTK+ 2.5.2 released!

This is a development release leading toward 2.6 series.

Make GTK+2 dependency optional.
Use the ld version script for non developer builds.
Add webkit_navigation_policy_decision_get_navigation_action() API and deprecated the methods and properties in WebKitNavigationPolicyDecision that are now redundant.
Add support for user scripts to WebKitUserContentManager.
Do not use GtkWindow:resize-grip-visible with recent GTK+ versions.
Fix caps negotiation failure in playback pipeline in GSTreamer media backend.
Rename translation domain to WebKit2GTK-4.0.
Install the processes in a versioned directory.

Thanks to all the contributors who made possible this release.