This makes the interface more comprehensible and allows for
input_item_node_Append[x] functions to be used for general node manipulation
without side effects, if needed in future.

 - remove pf_run no longer in use
 - attach object as soon as possible to benefit var heritage

for the video decoder on OMAP

It should fix it when input and output pictures don't have the same
properties (close #3063).

It will avoid selecting a non subtitle page at the core levels.

And replaced QVLCIconLabel with QVLCFramelessButton.

They are not supported.

They are not the same as the chroma plane are swapped.

  The module did not mark the subtitles it produces with "b_subtitle == true",
  which causes them to be handled as OSD, and thus allowing them to become
  out of sync unless video was streamed in real time...
Signed-off-by: Laurent Aimar <fenrir@videolan.org>