Change various mini object references to references to the refcounted object

examples/src/bin/glupload.rs

gstreamer-base/src/subclass/aggregator.rs

gstreamer-base/src/subclass/aggregator_pad.rs

gstreamer-base/src/subclass/base_sink.rs

gstreamer-base/src/subclass/base_src.rs

gstreamer-base/src/subclass/base_transform.rs

gstreamer-video/src/video_meta.rs

gstreamer-video/src/video_overlay_composition.rs

gstreamer/src/bufferlist.rs

gstreamer/src/event.rs

gstreamer/src/meta.rs

gstreamer/src/query.rs

gstreamer/src/sample.rs

gstreamer/src/subclass/element.rs

tutorials/src/bin/basic-tutorial-4.rs