change listening (and index fix)

added onChange listeners to elements for when their channels are updated.

Also notice that the information block structure is now:
```
<div class="channel-visualisation">
  <div class="broadcast-channels">
    <div class="channel"></div>
  </div>
  <div class="subscription-channels">
    <div class="channel listenerFunctionName"></div>
    ....
  </div>
</div>
```