OSMF SVN

Adding unit test for CompositeMetadataEvent.

Extending unit tests, and fixing a bug.

Adding null param to URL constructor in unit test.

Extending CompositeMetadata unit tests. Adding null checks to CompositeMetadata.

Removed ID check, as is optional now in newest Manifest Spec.

Disabled parse error test introduced in last checkin.

Initial refactoring of composition layer to support traits as base classes. So far only the composite audible and bufferable traits have been changed, the others are commented out.

Updated propeties of ignore.

Updated Manifest loader

Initial check-in of the captioning plugin and sample app.