Proposed changes to media Track and children

[David DeHaven]

> Option 1>
> Make the following changes to Track and it's subclasses:
> Changes to Track:
> - Add public final Locale getLocale(), returns a Locale if one is provided by the container or null if not
> - Add public final long getTrackId(), returns a unique numeric track ID that will be used by the stack to identify this specific track
> - Add public final Map<String,Object> getMetadata(), returns any metadata specific to this Track (returned Map is an UnmodifiableMap for security)
> 
> Changes to AudioTrack:
> - getLanguage(): deprecate, "use Track.getLocale() instead." Which is all that method does now anyways.

So that's essentially two votes for option 1. My time has been cut short on this project so I will go ahead and commit this change. If there are any objections please bring them up here or in JIRA and the media team can handle it.

-DrD-