Updated the plugin to be used for tag_cloud also

Hi, 
I have updated the plugin to be used for tag_cloud also.

Hope this helps someone.
Many Thanks for your work.
Screen shot attached below.

Example:
--------
In template files, add the following markups.

### source/_includes/custom/asides/category_cloud.html ###

    <section>
      <h1>Tag Cloud</h1>
        <span id="tag-cloud">{% tag_cloud bgcolor:#ffffff tcolor1:#00aa00 tcolor2:#00dd00 hicolor:#ff3333%}</span>
    </section>

    <section>
      <h1>Category Cloud</h1>
        <span id="category-cloud">{% category_cloud bgcolor:#ffffff tcolor1:#00aa00 tcolor2:#00dd00 hicolor:#ff3333%}</span>
    </section>

![tagscreenshot](https://f.cloud.github.com/assets/2206818/79807/d10508de-61ca-11e2-87fb-f75e4eb33720.jpg)