message: fix(demo-app): removed useless "div" container.
diff: -<div *ngFor="let chart of charts">
  <x-chartist
  + *ngFor="let chart of charts"
  class="col-md-6"
  [data]="chart.data"
  [type]="chart.type"
  [responsiveOptions]="chart.responsiveOptions"
  [events]="chart.events">
  </x-chartist>
  -</div>
  <div class="row">
  <div class="col-md-6">
  