Unify visual effects for quantumness

[HuangJunye]

Related to issue #13. We should decide on a visual effect to express quantumness/superposition, for example, scrolling rainbow color. Then we use this visual effect throughout the game.

[HuangJunye]

My idea is to make the game appear almost exactly like the classical Pong, only black and white. When quantumness comes in, the game suddenly become colourful. Issue #13 already mention usage in superposed balls and superposed paddles. We can also add scrolling rainbow (or whatever we decide at the end) in the title screen, for the letter "Q" in "QPong". At first, "Q" is just white as other letters in the title screen. When the player press any key to start playing, "Q" becomes scrolling rainbow for 0.1s to give the hint to the player, this is not like classical Pong, although it looks very similar.

[HuangJunye]

Perhaps the same visual effect can be used in the gate images too. (I haven't had a look at the new gate images yet). X gate behaves just like classical, so it should be black and white, while H gate brings the quantumness, so it should be scrolling rainbow.

[boland25]

@HuangJunye can you mock up a drawing of what you envision for this? might be more helpful to understand and we can show that to others for feedback