Log Message:
2.50.1 (stable):

Glib
* Dispatcher: Don't cast a HANDLE to an int on Windows.

Gio:
* Action: Include variant.h in the header.
* Application::get_default(): Correct the refcounting.
* SettingsSchemaSource: Correct the refcounting.

Gio::DBus
* Proxy: Fix memory leak in get_cached_property_names().

Documentation:
* Glib::Variant: Improve documentation of "maybe" types.
  Gio::ActionMap: Clarify doc of ActivateWithParameterSlot.

Build:
* C++11: Variant: Replace throw(std::bad_cast) with noexcept(false).
  See https://bugzilla.redhat.com/show_bug.cgi?id=1438766
* Visual Studio: Install the .pdb files.