Merge PR #4: Optional Callback

Closes #4.

Squashed commit of the following:

commit 715db0b624593d81f0e688554e8ca4e4f778b60b
Author: Dan Watson <watsond@imsweb.com>
Date:   Mon Jul 21 13:59:15 2014 -0400

    Missing newline

commit dada4a967993a8e21ba6cb2f9672417ea1905e2e
Author: Dan Watson <watsond@imsweb.com>
Date:   Mon Jul 21 13:56:46 2014 -0400

    Added an optional callback function to titlecase