Updated Serbian translation
Updated Serbian translation
Updated FSF's address
mainwindow: remove generic try / except.
project: cast remaining uncasted restriction fields.

Also check that value is not None before trying to cast it
(for example the preset system tries to pass None to these functions)

Fixes https://bugzilla.gnome.org/show_bug.cgi?id=720699
timeline: connect to the whole GUI to end marquee selection.

Fixes https://bugzilla.gnome.org/show_bug.cgi?id=723035
Updated German help translation
Updated Hungarian translation
pitivi: GESPipeline.add_timeline was rename GESPipeline.set_timeline
elements: Remove unused get_border_color method
timeline: Always set self.current_group in TimelineStage._dragEndCb
timeline: Selection cleanup
project: Avoid setting the selection field for a GESTimeline object

We set and use TimelineStage().selection = Selection().
The GESTimeline().selection = Selection() field removed in this commit
was simply not used anywhere.
timeline: Raise a proper exception if no element is found
timeline: Use proper value in debug statement
timeline: Avoid zooming in when setting the best zoom ratio
widgets: Fix the zoom slider not showing the initial zoom value
dogtail tests: Rename variable to clarify what it represents
dogtail tests: Reuse center method
medialibrary: Remove unused _trackElementAddedCb method