Major overhaul of scene transitions and game over

GameOver.gdshader

@@ -0,0 +1,14 @@
+shader_type canvas_item;
+
+void vertex() {
+	// Called for every vertex the material is visible on.
+}
+
+void fragment() {
+	// Called for every pixel the material is visible on.
+}
+
+//void light() {
+	// Called for every pixel for every light affecting the CanvasItem.
+	// Uncomment to replace the default light processing function with this one.
+//}