gdbus: Add helper functions for simple D-Bus clients
gdbus: Add support for D-Bus client proxies
gdbus: Add support for D-Bus client properties
gdbus: Add support for complex D-Bus client properties
gdbus: Deep copy of variants also requires a signature
gdbus: Add support for setting D-Bus client basic properties
gdbus: Use a GPtrArray for the match rules
gdbus: Set property changed filter match rule for each proxy
gdbus: Handle property changed signals and update property
gdbus: Add callback support for handling property changes
gdbus: Add support for D-Bus client method calls
gdbus: Fix issue with unref of client in connect handler
gdbus: Fix issue with unref of client while parsing interfaces
gdbus: Fix race condition with creating duplicate client proxies
gdbus: Add helper for sending async error replies
gdbus: Increase the method call timeout to 5 minutes
build: Compile support for new D-Bus client helpers
doc: Add USAT certification status document
Release 1.12
gdbus: Avoid using g_ptr_array_new_full convenience function

The g_ptr_array_new_full function only got introduced with GLib 2.30
and to avoid requiring a newer GLib use g_ptr_array_set_free_func instead.