Add strokeWidth property to the Sparkline Model

![Example Output](https://dl.dropboxusercontent.com/u/81092564/photos/sparkline-stroke.png)

I've added a strokeWidth property to the sparkline. I was unable to implement this change with CSS alone, and so I've moved it into the sparkline model. I implemented it as a function rather than simple int so that it could be based on input data.

Unfortunately, this PR includes a commit to convert the CRLF in two files. I know that this is churn that you may not want, but it may be helpful for future pull requests.