[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
videoplayer: adapt lateness detection and dropping to buffering
video player: present correct pts to user for a/v sync (after buffering in renderer)
videoplayer: some rework and documentation
renderer: bump buffers to 5
videoplayer: update frametime, it might change due to fps detection
videoplayer: give streams with invalid fps a chance for fps detection
dvdplayer: allow rewinding at end of stream, do a seek after rewind
X11: ditch SDL for video and window events
X11: Add xbmc icon
X11: add SDL joystick until we have a better solution
X11: factor out code handling device reset notification