Function unionBounds

unionBounds(b1, b2): {
    height: number;
    width: number;
    x: number;
    y: number;
}
Parameters
- b1: Bounds
- b2: Bounds
Returns {
    height: number;
    width: number;
    x: number;
    y: number;
}
- height: number
- width: number
- x: number
- y: number