Add dusk background

Assets/Prefabs.meta

Assets/Prefabs/Background.prefab

Assets/Prefabs/Background.prefab.meta

Assets/Record/Recorded/test.meta

Assets/Record/Recorded/test/0.txt.meta

Assets/Record/Recorded/test/1.txt.meta

Assets/Record/Recorded/test/2.txt.meta

Assets/Record/Recorded/test/3.txt.meta

Assets/Record/Recorded/test/4.txt.meta

Assets/Record/Recorded/test/mean.txt.meta

Assets/Record/Recorded/test/variance.txt.meta

Assets/Scenes/Record.unity

Assets/Scenes/Replay.unity

...res/Backgrounds/Materials/blackwhitestripe_background.mat

...res/Backgrounds/Materials/gradient_stripes_background.mat

...ackgrounds/Materials/gradient_stripes_background.mat.meta

Assets/Textures/Backgrounds/blackwhitestripe_background.png

Assets/Textures/Backgrounds/blackwhitestripe_circle.png

Assets/Textures/Backgrounds/gradient_stripes_background.png

...Textures/Backgrounds/gradient_stripes_background.png.meta