When cancel Colorpicker, it set wrong value for component

Hi @artf, After seeing around the colorpicker, I think the problem is that the spectrum doesn't have the same value as model when user changes input. So I attempted to sync the value of spectrum and model, and it could fix the issue. Here is my solution:

// InputColor.js
  /**
   * Set value to the model
   * @param {string} val
   * @param {Object} opts
   */
  setValue(val, opts = {}) {
    const model = this.model;
    const def = model.get('defaults');
    const value = !isUndefined(val) ? val : !isUndefined(def) ? def : '';
    const inputEl = this.getInputEl();
    const colorEl = this.getColorEl();
    const valueClr = value != 'none' ? value : '';
    inputEl.value = value;
    colorEl.get(0).style.backgroundColor = valueClr;

    // This prevents from adding multiple thumbs in spectrum
    if (opts.fromTarget || (opts.fromInput && !opts.avoidStore)) { // when input changed, update value in spectrum
      colorEl.spectrum('set', valueClr);
      this.noneColor = value == 'none';
    }
  },

What do you think about this? If it's ok, I could submit a PR.

Thank you.

I found out that this bug also happen if you change the input with any value, then immediately open colorpick then cancel it by clicking outside (not canvas).