undo: Undo redo logic for assets is now implemented in project.

https://bugzilla.gnome.org/show_bug.cgi?id=739251
undo: Disconnect from the signals correctly.

https://bugzilla.gnome.org/show_bug.cgi?id=739251
mainwindow: improve signal disconnecting.

https://bugzilla.gnome.org/show_bug.cgi?id=739251
undo: disconnect correct handlers when layer is removed.

https://bugzilla.gnome.org/show_bug.cgi?id=739251
undo: No need for class attribute actions.

https://bugzilla.gnome.org/show_bug.cgi?id=739251
previewers: hardcoded path manipulations are bad.

And I should feel bad.

https://bugzilla.gnome.org/show_bug.cgi?id=739251
undo: Add LayerAdded and LayerRemoved actions.

https://bugzilla.gnome.org/show_bug.cgi?id=739251
Start implementing scenario serialization

https://bugzilla.gnome.org/show_bug.cgi?id=739251
scenarios: Serialize play / pause

https://bugzilla.gnome.org/show_bug.cgi?id=739251
pitivi: Add a way to let user decide where to save scenario files

Through the PITIVI_SCENARIO_FILE env varible

+ Make sure to state that our scenarios handle state changes

https://bugzilla.gnome.org/show_bug.cgi?id=739251
project: Override GES.Timeline.commit to save commit actions

Now scenario have to contain all information about timeline
committing, make sure that the commit action is serialized.

https://bugzilla.gnome.org/show_bug.cgi?id=739251
utils:timeline: Serialize action for container editing

https://bugzilla.gnome.org/show_bug.cgi?id=739251
Serialize seek actions and fix state change action serialization

https://bugzilla.gnome.org/show_bug.cgi?id=739251
autopep8 WORKS, let's just use it!

https://bugzilla.gnome.org/show_bug.cgi?id=739251
Encourage developers to use autopep8

https://bugzilla.gnome.org/show_bug.cgi?id=739251
Serialize GES.Clip.split actions

https://bugzilla.gnome.org/show_bug.cgi?id=739251
project: Serialize the setting of GES.Track.restriction_caps

https://bugzilla.gnome.org/show_bug.cgi?id=739251
Serialize the setting of asset on transition

And simplify the way we write action in the file

https://bugzilla.gnome.org/show_bug.cgi?id=739251
application: Add 'wait' action between actions

+ stop everything when quitting.

https://bugzilla.gnome.org/show_bug.cgi?id=739251
clipproperties: Commit the timeline when removing an efect

+ No need to flush the pipeline if we already commited (and now
that the commit actually had the same effect)

https://bugzilla.gnome.org/show_bug.cgi?id=739251