Addes necessary model for SceneMap.
Adds FieldName and Selection attributes.
Adds new scene map actions and tests.
Changes some actions and tests.
DraggableGridLayout refactoring. New DropGridEvent, DropListEvent, etc.
GridLayout improvements.
Adds SceneMapWidget and SceneWidget.
Updates HomeView.
Renamed AddToMap to IncreaseMapSize action.
Adds some Q utility methods.
Changes actions to generate Cells in the SceneMap.
Merge pull request #692 from RotaruDan/modelSceneMap

SceneMapWidget, model...
Adds ToggleIconButton.
Import button is always shown on screen. Also widgets use the new icons. The correct frame is selected when pausing.
New icons used. Small bugfix while trying to center at a specified index after undoing an import action.