ffmpeg: dxva2_h264: set the correct ref frame index in the long slice struct

The latest H.264 DXVA specification states that the index in this
structure should refer to a valid entry in the RefFrameList of the picture
parameter structure, and not to the actual surface index.

Fixes H.264 DXVA2 decoding on recent Intel GPUs (tested on Sandy and Ivy)
ffmpeg: dxva2_h264: add a workaround for old intel GPUs

Old Intel GPUs expect the reference frame index to the actual surface,
instead of the index into RefFrameList as specified by the spec.

This workaround should be set when using one of the "ClearVideo" decoder
devices.
[dxva] Add support workaround for Intel H.264 VLD, no FGT, ClearVideo decoder.
[dxva] Prefer standard Microsoft H.264 device instead of Intel H.264 VLD, no FGT (ClearVideo).

This fix h264 decoding with refs > 11 on recent Intel GPUs (SNB/IVB). The latest Intel drivers for IVB/Haswell already has no support old Intel H.264 VLD, no FGT (ClearVideo) device, so this actually needs for SNB and older.
[python] fix scripts run directly that aren't an add-on. fixes #14265
[epg] adjust title to the left edge for the first items in timeline view

This adjust the title of the first item in EPG timeline view if you
scroll so it always starts at the left edge of the programme grid.
cosmetics: remove unnecessary NULL checks + code formatting
[gui] fix: reduce child item width by -10px every time you call EnlargeWidth()
cosmtics: fix comments
[confluence] fix: timeline item label overlapping
[gui] fix: don't add m_posX/m_posY to width/height for SetMaxRect() on
left aligned list labels
Merge pull request #4376 from xhaggi/epg-timeline

[epg] adjust title to the left edge for the first items in timeline view
Merge pull request #4382 from jmarshallnz/fix_non_addon_scripts

[python] fix scripts run directly that aren't an add-on. fixes #14265
[iossink/osxsink] - don't deadloop in drain when device is gone - but
handle timeout
[iossink/osxsink] - fixed - condvar has to wait on the mutex - not on the singlelock
Merge pull request #4383 from Memphiz/osxbreakdrain

[osxsink] - fix deadloop in drain
Merge pull request #4228 from afedchin/dxva_h264_intel

[DXVA] Fix h264 deconding with refs > 11 on recent Intel GPUs (SNB/IVB)