Initial commit
Reorganize the file structure
Make the overlay a little lighter
Use a more responsive solution for centering the modal
Add a callback option when opening a modal
Update README
Organize the code to follow the Revealing Module Pattern
Add a very slight performance optimization
Reorganize the 'isInitialized' check and move 'private' methods
Add layered modals, move callback parameter into options

- Add the ability to have multiple layers of modals
- Move callback paramater into 'onLoad' option
- Add a 'cancel' ability
Automatically determine the 'z-index' offset from CSS
Pass 'modal-content' element into callback functions
Update README with new options
Add close/cancel callback examples
Update comments
Delegate the overlay click event to the document body
Reorganize CSS rules
Update the README with more detailed documentation
Add line-breaks to the README
Add a horizontal-rule between usage functions. Remove semi-colons.