registry: don't recreate features on first use. Fixes #584389
The first time one calls gst_element_factory_make(), gst recreates the plugin feature and the element factory. As a side effect we ref the class to fill in detail we already have filled from the registry cache. This patch changes the behaviour to just update the existing entries. The factory is now attached to the type and set in gst_element_base_class_init().
Showing with 71 additions and 28 deletions