Return a pointer to vlc_va_conn_t.

Use --ffmpeg-vaapi-x11 in combination with --ffmpeg-hw. It uses
the vaapi to decode pictures and display it without copying it back
to main memory.
When --no-ffmpeg-vaapi-x11 is used then the picture is copied from
the GPU to main memory and displayed later by another vout. This uses
more CPU then when the picture is displayed from the GPU contenxt directly.

Implement picture pool for VAAPI-X11 vout.

Use vlc_va_* wrapper to call vaInitialize and vaTerminate

Initialize/terminate libva only once. VAAPI calls are now being used by
2 modules which only have interaction with each other through vlc core.
Both modules (codec and vout) can be initiated independently they should
not call vaIntialize (or vaTerminate) one after each other (or simultanously).

Add option to select stream_output module to enable an es by default.

Video output VAAPI-X11 (-V vaapi-x11) depends on --ffmpeg-hw to be enabled.

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

This fixes the crash when Media Library tries to add "My Videos" / "My
Pictures" / etc. playlist entries to a ML when browsing them through "My
Computer" service discovery.

Signed-off-by: Laurent Aimar <fenrir@videolan.org>

Remove tabs, trailing spaces, and write-only variables

This partially reverts commit add821b0.

Caused by [231a9671]
Sorry for the disturbance

(we might need a PSK box later)