message: Improve the logic about calculate vertices
  Reason:
  * Do similar things in similar way :  compute left / top , then add width/height .
  * A very very very very (...* 1000000) bit little performance improvement :  one `-` & one `*` become one `+`.
  * fix some words in document.
diff: @@ -212,11 +212,11 @@ export default class Sprite extends Container
  }
  else
  {
  - w0 = orig.width * (1 - anchor._x);
  - w1 = orig.width * -anchor._x;
  + w1 = -anchor._x * orig.width;
  + w0 = w1 + orig.width;
  - h0 = orig.height * (1 - anchor._y);
  - h1 = orig.height * -anchor._y;
  + h1 = -anchor._y * orig.height;
  + h0 = h1 + orig.height;
  }
  // xy
  @@ -269,11 +269,11 @@ export default class Sprite extends Container
  const tx = wt.tx;
  const ty = wt.ty;
  - const w0 = (orig.width) * (1 - anchor._x);
  - const w1 = (orig.width) * -anchor._x;
  + const w1 = -anchor._x * orig.width;
  + const w0 = w1 + orig.width;
  - const h0 = orig.height * (1 - anchor._y);
  - const h1 = orig.height * -anchor._y;
  + const h1 = -anchor._y * orig.height;
  + const h0 = h1 + orig.height;
  // xy
  vertexData[0] = (a * w1) + (c * h1) + tx;
  @@ -440,7 +440,7 @@ export default class Sprite extends Container
  *
  * @static
  * @param {number|string|PIXI.BaseTexture|HTMLCanvasElement|HTMLVideoElement} source Source to create texture from
  - * @return {PIXI.Sprite} The newly created texture
  + * @return {PIXI.Sprite} The newly created sprite
  */
  static from(source)
  {
  @@ -538,8 +538,8 @@ export default class Sprite extends Container
  }
  /**
  - * The tint applied to the sprite. This is a hex value. A value of
  - * 0xFFFFFF will remove any tint effect.
  + * The tint applied to the sprite. This is a hex value.
  + * A value of 0xFFFFFF will remove any tint effect.
  *
  * @member {number}
  * @default 0xFFFFFF
  