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)

// Sizing shortcuts

.size(@width; @height) {
  width: @width;
  height: @height;
}

.square(@size) {
  .size(@size; @size);
}