Make animations work in the options screen

internal/ui/noninteractive.go

@@ -0,0 +1,20 @@
+package ui
+
+import (
+	"github.com/hajimehoshi/ebiten"
+	"image"
+)
+
+// A non-interactive element is not a widget; it merely displays some pixels and
+// may optionally have a tooltip for display within bounds.
+//
+// For non-animated non-interactive elements, just give them a single frame.
+type noninteractive struct {
+	bounds  image.Rectangle
+	frames  animation
+	tooltip string
+}
+
+func (n *noninteractive) image(step int) *ebiten.Image {
+	return n.frames.image(step)
+}