e.preventDefault() inside passive event listener in mobile devices
With `"react-color": "^2.17.0"`

In Chrome 71.0.3578.98, with devtools responsive mode, the following warning is emitted.

![2019-01-28 18 01 56](https://user-images.githubusercontent.com/5250706/51824884-d6252a00-2326-11e9-804d-9f7a5affea84.png)

It look like React implicitly `addEventListener`s `touchmove` event as `{ passive: true }`.

Since [you should not fire `e.preventDefault()` in `touchmove` handler](https://www.chromestatus.com/features/5093566007214080), which `Saturation` component is violating it.

https://github.com/casesandberg/react-color/blob/8bde391b44d9336bccae91757b748b32d91bb1cd/src/components/common/Saturation.js#L20-L26

Fundamentally it is caused by `saturation.calculateChange()`, so it seems this could be solved by

1. making `.calculateChange` not requiring `Event` object
2. not using `Saturation.this._handleChange` for `onTouchmove`, replacing to another event handler

