ffmpeg: bump to 2.4
ffmpeg: adapt win32 dlls to major versions of 2.4
[dvdplayer] Fix for timestamp correction when no audio or no video

If audio or video track is missing, we don't have to wait for the other track to have a matching timestamp jump
Also compare dts rather than correction values as suggested by FernetMenta
Merge pull request #5345 from popcornmix/correctioncorrectioncorrection

[dvdplayer] Fix for timestamp correction when no audio or no video
Merge pull request #5371 from FernetMenta/ffmpeg24

ffmpeg: bump to 2.4
omxplayer: Reset codec on flush to stop a stale timestamp from being returned
[rbp] Hardware accelerated resampling

This replaces the format conversion, up/down mixing and resampling code from ActiveAE with a GPU accelerated version.
Should significantly reduce CPU when using paplayer or dvdplayer.

Requires updated firmware
[rbp/omxplayer] When opening a stream don't try to update gui so often
[ffmpeg] Speed up wtv index creation

The index creation is O(N^2) with number of entries (typically thousands).
On a Pi this can take more than 60 seconds to execute for a recording of a few hours.

By replacing with an O(N) loop, this takes virtually zero time
adds GetTvShowSeasons
move AddSeason() public.
adds GetArt function to (video) scraper, allowing art to be fetched given the video identifier.
refresh season art if a new season is found that isn't recorded in the database yet. Fixes #14339
REMOVEME: updated thetvdb.com scraper to support art updates
[omx] Report decoded image name
logging: Add microsecond timer to log messages
videoplayer: adapt lateness detection and dropping to buffering
video player: present correct pts to user for a/v sync (after buffering in renderer)
[hifiberry] Hack: force it to be recognised as IEC958 capable to enable passthrough options
Move the reference-counting of Begin and End calls from DX and GL source files into GUIFontTTF.cpp.