Small default FocusItemStyle improvements.
Adds necessary actions and tests.
FocusItemList and LinearLayout improvements.
Renamed FramesTimelineTest to AnimationEditorTest.
Adds AnimationEditor.
Convenence methods and attributes.
FrameWidget refactoring (duplicate, delete, correctly managing the time...).
FramesTimeline refactoring. WOrks with selection, undo/redo, drag and drop...
Adds PreviewView, a view that holds an FramesComponent and displays/updates it when the model changes.
Format after rebase.
Comments addressed.
Merge pull request #672 from RotaruDan/AnimationEditor

Animation editor
Editor remembers last loaded project
Scenes are fit first time they are loaded