Check images Task

Hey Jim,

I've created a the `check-images` task that works as we want. However, I configured the check-images task to only need the article name, not the complete directory path (e.g. `articles/01-beginning-liferay-development/01-writing-your-first-liferay-application`), which is currently required by the `article-to-html-win` task. Therefore, since the `article-to-html-win` and `check-images` tasks both use the same ${article} input, we can only currently have one or the other work.

I wanted to discuss with you how we'd like to pursue specifying an article for these types of ant tasks. It's a bit cumbersome having to type a multi-directory article specification, but we'll need to develop a bit more not to require this for tasks like `article-to-html-win`.

We can discuss this more in-depth Monday if you'd like, but wanted to let you have a peek at what I've done to this point and where we stand. Thanks!