promotion dialog: set transient for main window
promotion dialog: use header bar
Updated Russian translation
doap: remove Jason
Update POTFILES.skip
Remove 3D mode

https://mail.gnome.org/archives/games-list/2014-June/msg00006.html

https://bugzilla.gnome.org/show_bug.cgi?id=720284
Make pause overlay transparent

The pieces are hidden anyway, so this results in us showing an empty
board.

https://bugzilla.gnome.org/show_bug.cgi?id=720284
fixup: remove 3D-mode gsettings keys

https://bugzilla.gnome.org/show_bug.cgi?id=720284
fixup: remove 3D assets

https://bugzilla.gnome.org/show_bug.cgi?id=720284
Do not directly pause/unpause the chess clock

https://bugzilla.gnome.org/show_bug.cgi?id=728202
Move widgets around in preferences.ui

Don't change the dialog at all, just move these to more sane positions
within the file.
preferences: fix size of piece style combo

Easy to see what's wrong now that things are in the right position
Improve time control handling

Set the game's time limit, not a duration, so that selecting one hour
gives each player a time limit of one hour (rather than 30 minutes).

This also fixes our interpretation of the TimeControl field.
Set a reasonable min size for the ChessView
Updated POTFILES.in and POTFILES.skip
Updated Spanish translation
Updated Greek translation
Prepare 3.13.4
Mention removed dependencies in NEWS
Merge branch 'mallard-help' of ssh://git.gnome.org/git/gnome-chess into mallard-help