Implemented timerange for mdplayer and use of it in widget Segment: if enable (option is use_timerange) when clicking a segment user can only read the video on current segment + adapted other widgets that need to detect segment to be able to use this option if it is enable so that segment detection is smoother + adjusted API testing form on iframetesting to use the correct api (form is still hidden by default)

// Labels

.label-variant(@color) {
  background-color: @color;

  &[href] {
    &:hover,
    &:focus {
      background-color: darken(@color, 10%);
    }
  }
}