gst/: Avoid excessive typechecking in macros.

gst/: Avoid excessive typechecking in macros.

Original commit message from CVS:
* gst/base/gstbasesink.c: (gst_base_sink_preroll_queue_empty),
(gst_base_sink_do_sync), (gst_base_sink_handle_event),
(gst_base_sink_chain), (gst_base_sink_change_state):
* gst/base/gstbasesink.h:
* gst/base/gstbasesrc.h:
* gst/gstelement.h:
* gst/gstevent.h:
Avoid excessive typechecking in macros.

* gst/gstminiobject.c: (gst_mini_object_get_type),
(gst_mini_object_init), (gst_mini_object_new),
(gst_mini_object_free):
* gst/gstobject.c: (gst_object_class_init), (gst_object_init),
(gst_object_finalize):
Remove cruft code, optimize alloc_trace.