libdvdnav runs dvdread-config to update CFLAGS and LDFLAGS with libdirs, includirs and libraries but wrongly with locations on the buildsystem. this breaks crosscompiling. We fix this with providing a own 'dvdread-config' file which dont inject /usr/include and /usr/lib in our *CFLAGS.
Input: fix Accelerometer being detected as joystick
Fix compilation error due to missing include.

This fixes compilation error due to missing header.

 SDL_anigif.cpp: In function ‘int AG_LoadGIF_RW(SDL_RWops*, AG_Frame*, int)’:
 SDL_anigif.cpp:293:37: error: ‘malloc’ was not declared in this scope
   gd = (gifdata*)malloc( sizeof(*gd) );
                                     ^
 SDL_anigif.cpp:418:11: error: ‘free’ was not declared in this scope
   free( gd );
           ^
 make: *** [TexturePacker] Error 1
Fix compilation error related to removed structure field by ffmpeg.

ffmpeg removed reference_dts field in struct AVStream.

Related ffmpeg commit:
  http://git.videolan.org/?p=ffmpeg.git;a=commitdiff;h=2ba68dd044ca8fc591139c05563840f546a9c0c0
bump GUI ABI to 5.0.0 due to recent skin core changes
[pvr] show gaps on epg timeline grid
DVDSubtitleStream: better detect stream encoding and optimization
Use BOM detection for all supported charsets, not only UTF-8 and UTF-16LE
Do not double convert subtitle->wstring->UTF-8. Use direct conversion subtitle->UTF-8
additionally: CharsetConverter: subtitleCharsetToW -> subtitleCharsetToUtf8
[confluence] adds info area for current selected epg item
[info] factor out parsing of [] so it can be used to parse other strings
[info] [] parsing can use the new ReplaceString() function
[info] adds [] to info labels, allowing skinners to specify a number. Required as by default numbers are taken as a reference into localized strings.  In future, this will be dropped in favour of [] only being used as this will benefit translation
[rbp/omxplayer] Cosmetic: Avoid DVDPlayer in logging message

It makes people incorrectly think DVDPlayer has been running
[spectrum] cosmetic: Use static where appropriate
[rbp] Remove PiAudio engine
[rbp] Add PiAudio sink
[spectrum] Draw spectrum as a single object

glDrawElements is called 256 times per frame, once for each bar. It is more efficient to batch up larger blocks.
This change draws the specrum with a single glDrawElements call.

Looking at visualisation in full screen mode, it used to top out at 75 fps. With this PR it can hit 125 fps.
[rbp/omxplayer] When reencoding thumbnails preserve orientation

Currently reencoded thumbnails are displayed without original orientation flag applied.
However we can write the Orientation field of IFD0 data, which means the cached thumbnail will be displayed correctly when decoded
[date/time] Return a bool from SetDate/Time to indicate a successful, valid, date
[date/time] validate SetFromDBDate() a little better
[date/time] have SetFromDateString() first attempt SetFromDBDate() before attempting to parse for a 'Sunday, April 15 2006' style date