OSMF SVN

[dvr proto] reinstating VideoElement clause that instantiates a DVRCast trait.

[dvr proto] integrating trunk changes.

[dvr proto] integrating trunk changes.

[dvr proto] integrating trunk changes.

PARB changes:

Removing MediaContainerGroup. Exposing the inner layout renderer publicly in order to facilitate container nesting. Updating NestedMediaContainers sample accordingly.

Overriding display list management functions on MediaContainer to throw an exception on direct invocation. As a result, layout renderers are no longer capable of adding display objects onto a container, but this is resolved by LayoutRendererBase now emitting events requesting display object (un)staging or index adjustment. LayoutTargetSprite and MediaElementLayoutContainer have been updated accordingly.

PARB changes: making add, remove and contains methods public on the ASDocs. Refraining from adding shielding for adding custom display objects to the sprite, for a LayoutRenderer must be capable of doing so.

PARB changes: LayoutRendererProperties, remove "ment" from horizontal- and verticalAligment. Set MIDDLE constant to "middle". Updating unit tests and client code accordingly.

PARB changes: make measuredWidth and height, displayObject, measure and layout public on ASDocs.

PARB changes: mark events @private, remove LayoutRenderer mentionings on layout and measure routines.

PARB changes: Remove ILoadedContext, use LoadTrait subclasses to hold media-specific objects.