Draw the MultiSlider onto its canvas context using the current .__value property.
@memberof MultiSlider
@instance
function draw() {
    // draw background
    this.ctx.fillStyle = this.background;
    this.ctx.strokeStyle = this.stroke;
    this.ctx.lineWidth = this.lineWidth;
    this.ctx.fillRect(0, 0, this.rect.width, this.rect.height);

    // draw fill (multiSlider value representation)
    this.ctx.fillStyle = this.fill;

    var sliderWidth = this.style === 'vertical' ? this.rect.width / this.count : this.rect.height / this.count;

    for (var i = 0; i < this.count; i++) {

      if (this.style === 'horizontal') {
        var ypos = Math.floor(i * sliderWidth);
        this.ctx.fillRect(0, ypos, this.rect.width * this.__value[i], Math.ceil(sliderWidth));
        this.ctx.strokeRect(0, ypos, this.rect.width, sliderWidth);
      } else {
        var xpos = Math.floor(i * sliderWidth);
        this.ctx.fillRect(xpos, this.rect.height - this.__value[i] * this.rect.height, Math.ceil(sliderWidth), this.rect.height * this.__value[i]);
        this.ctx.strokeRect(xpos, 0, sliderWidth, this.rect.height);
      }
    }
  }