changed: Auto extract thumbs/flags for webdav
GUIEpgGridContainer: validate scroll offsets as well as they are used to calculate rendered blocks
GUIEpgGridContainer: don't select first item on mouse/touch event on empty programme block
GUIEpgGridContainer: don't react on clicking channel list
GUIEpgGridContainer: add panning gesture
GUIControlGroupList: add panning gesture
Add media parameter to Playlist.Item directory type

Allow complete control from remote of the media to add, now permit a correct Player.Open on directories with mixed items.
Also permit to have metadata loaded when files are added from Player.Open
Forcing a wrong type for a specific playlist return an invalid params.
Now also authorize to queue videos to pictures playlists
[Python] Adds autoclose to python's yesno dialog.
Add python-imaging dependency its been a ppa dep since 2011

Add zlib1g-dev Readme.ubuntu since has been part of ppa deps for a while too
and its part of readme.linux.

Full A-Z Alphabetical sort on both readmes's as per wsnipex comments

Squash all into 1
fixed: The db check for streamdetails was wrong
changed: Improve comment
fixed: Streamdetails & resume-bookmark saving etc. for bluray eg. folders didn't work (fixes #14288)
[release] version bump to 13.0 alpha4 as we start new merge window.
[addons] sync scrapers with repo
Merge pull request #2658 from arnova/bluray_flag_fix

fixed: Streamdetails & resume-bookmark saving etc. for bluray folder...
[musicdb] cosmetic: change to using XMLUtils for the album XML getters/setters
[musicdb] cosmetic: artist.cpp XML cosmetics
[musicdb] cosmetic: rename song.iAlbumId to song.idAlbum
[musicdb] cosmetic: restructured MusicDatabase.h to be a bit clearer and add some comments
[musicdb] fix: 'include artists who appear only on compilations: off' didn't work