Completely reworked subtitle queue.

The new queue should be a bit faster than the older one for a similar number of buffered subpictures. It should also work much better when the number of subpicture becomes important.
Subtitle queue: Make the queues aware of subtitles with unknown end time.
ISR: Add the ability to disable subtitle animation even when using no buffering.
Cosmetics: Use a short alias instead of GetRenderersSettings().
Put the subpic queue settings in a structure for easier use.
ISR: Add the ability to choose at which state an animated subtitle will be rendered when the animation is turned off.
Sync renderer: Use TRACE to print debug message.
CPPageSubtitles: Various cosmetics.

Reduce the visibility of variables and functions, remove unused variables and functions, use better name.
ISR: Animated subtitles: Add the ability to control the animation rate.
Subtitle queue: Correctly handle the cases when rendering is paused.

In such cases, try to block until the subpic is ready since the frame won't be refreshed and the subtitle wouldn't be displayed after seek or resize if the queue is too slow.
SubPicAllocatorPresenter: Protect SetSubPicProvider with a lock.

Stop relying on the global subtitle lock since it can easily create deadlocks.
Subtitle queue: Add the ability to share the lock on the subtitle provider.

The queue can access the subtitle provider concurrently in a read-only manner that allows sharing the same lock to improve the performance.

That is if the queue already owns the lock, it doesn't have to lock again, just ensure that the lock won't be released too early.
Subtitle queue: Give more control on the queue policy when it runs late.

Let the user choose between dropping some subpics (old behavior, now the default) and blocking until the queue catches up (possibly leading to dropped frames by the video renderer).
Subtitle queue: Re-enable the queue for madVR but always advise blocking.

madVR fetches the subpic when rendering not when presenting so we can always be blocking without impacting the performance too much.