OSMF SVN

PARB refactoring: Remove IMediaReferrer interface and CREATE_ON_LOAD type. The IMediaReferrer interface has been supplanted by a mediaElementCreationNotificationFunction property on MediaFactoryItemType. This callback is invoked any time the MediaFactory creates a new MediaElement. Thus, the MediaFactoryItem from the PluginInfo can coordinate any cross-referencing between its MediaElements and the factory's created MediaElements. And given that CREATE_ON_LOAD was introduced to ensure that the MediaFactoryItem's MediaElement could pick up references to other created MediaElements, that type is no longer necessary because the MediaFactoryItem could specify a notification callback, and do the initialization work it wanted to do at "create on load" time in its own constructor. In other words, by decoupling MediaElement referencing from the MediaElements themselves, we remove the need for CREATE_ON_LOAD.