Add label on source property for html5 video for Video plugin

[reaua001]

Summary

I noticed when using videojs and another tool to allow the video quality switching the label and selected does not pass

Basic example

Code changes starting from line 335

var html5VideoMarkup = '';
for (var i = 0; i < html5Video.source.length; i++) {
    var type = html5Video.source[i].type;
    var label = html5Video.source[i].label;
    var selected = html5Video.source[i].selected;
    var attr = type ? "type=\"" + type + "\" " : '';
    attr += label ? "label=\"" + label + "\" " : '';
    attr += selected ? "selected=\"true\"" : '';
    
    html5VideoMarkup += "<source src=\"" + html5Video.source[i].src + "\" " + attr + ">";

Motivation

Adding the label allows the other tools to grab that information and display properly
Adding selected allows the default selected