Display overlay text in the UI

We still have fonts to do, so this is very ugly, but it at least shows
*something* on the screen now.

internal/assetstore/object.go

@@ -94,7 +94,6 @@ func (o *Object) Sprite(idx int) (*Sprite, error) {
 	if sprite := o.sprites[idx]; sprite != nil {
 		return sprite, nil
 	}
-	log.Printf("Loading sprite %v:%v", o.raw.Name, idx)
 
 	if o.raw.Sprites[idx] == nil {
 		if err := o.raw.LoadSprite(idx); err != nil {