[gui] adds listitem info label inprogress to determine if epg item is in progress

This adds a new listitem info label inprogress which indicates if the
associated epg tag points to a current ongoing program.
Added Container.IsUpdating
[builtins] PlayMedia() should use a sort order appropriate for the items. fixes #15136
fix resume behavior for plugins with stack  

Resume behavior for local files (.-partN) are not corrupted.
http://forum.xbmc.org/showthread.php?tid=192690
Merge pull request #4616 from kit500/master

fix resume behavior for plugins with stack
Merge pull request #4601 from jmarshallnz/play_media_sort_order

[builtins] PlayMedia() should use a sort order appropriate for the items
[gui] fix incorrect parsing of relative <width> and <height> tags
Merge pull request #4531 from Black09/container-isupdating

Added Container.IsUpdating
Merge pull request #4033 from xhaggi/pvr-listitem-isactive

[gui] adds listitem info label inprogress to determine if epg item is in progress
[depends] move ffmpeg to unified deps
[configure] remove internal ffmpeg
remove ffmpeg from tree
ffmpeg: remove dll wrappers
add ffmpeg lock manager
todo: refactor to own file
ffmpeg: move callbacks into separate file
remove ffmpeg dlls from generated headers
not removing win32 as this might still be needed?
[rpi] setup-sdk.sh: allow overriding of buildroot and xbmc install paths
also don't require root if not needed
add ffmpeg makefile for rpi
[WIN32] download and compile ffmpeg from remote source.
[WIN32] make XBMC compile, build and run with the ffmpeg link libraries.