OSMF SVN

Pre-PARB metadata changes: Merge Facet and KeyValueFacet. Default facet uses a Dictionary, clients can extend if they want a different underlying structure. Update TemporalFacet accordingly. Disable some of the TemporalFacet API that's only used for test apps, we need to vet this a bit further. Update unit tests and samples.

Pre-PARB metadata changes: Merge IIdentifier and ObjectIdentifier, rename to FacetKey. Make similar adjustments to TemporalFacet class. Move TemporalFacetEvent to events folder. Update unit tests and samples.

PARB changes: Merge seekBegin and seekEnd event types into a single seekingChange event type. Add seeking as a getter to the SeekEvent class. Update test code and samples accordingly.

PARB changes: Hide URL/FMSURL, use strings instead. To support the FMS useInstance use case, modify StreamingURLResource to take a urlIncludesFMSApplicationInstance param, which NetConnectionFactory respects. Update unit tests and samples.

PARB changes: Remove references to URL within metadata APIs, where Strings would suffice.

PARB changes: Remove unload and query methods from PluginManager. We lack compelling use cases for those methods, but can easily re-add them later if we come across some.

Fix some stray references to TemporaProxyElement and the old package structure.

PARB changes: Rename PluginLoadEvent to PluginManagerEvent.

PARB changes: Refactor MediaFactory and Loader classes:
- MediaInfo becomes MediaFactoryItem. All MediaFactory and plugin-related APIs are updated accordingly. The rule of thumb is to use "item" on MediaFactory, and "mediaFactoryItem" on the plugin classes (since the former are already qualified, whereas the latter are not).
- Remove IMediaResourceHandler. Add canHandleResource to LoaderBase. Make handler function a Function to pass to MediaFactoryItem's constructor.
- Merge resolver interfaces/classes into MediaFactoryItemResolver, which defaults to selecting the first one.
- Make LoaderBase load/unload methods final. Add protected methods to execute the load, so that we can ensure validation takes place first.
- Update all unit tests and sample apps accordingly.

PARB feedback: Allow MediaElement subclass constructors to have default params. This involved moving the ILoader param to the second param, and providing a default when no loader is provided. For subclasses (like VideoElement) for which multiple loader types are supported, the implementation now chooses the appropriate one based on the resource type.