Don't use a drag plane to compute face offsets when resizing brushes.

Signed-off-by: Kristian Duske <kristian.duske@gmail.com>
Focus map canvas when dropping an entity.
Better precision for ResizeBrushesTool.
Autosave when exiting app / closing a map.

Signed-off-by: Kristian Duske <kristian.duske@gmail.com>