Changes:
* Changed dialog.content to dialog.data
* Changed remove() function to close()
- Added a parameter to close() for external calls
* Removed iframeId option
* Removed cloneContent option
- Completely changed the way SimpleModal handles the data (see below)
* Added overlayCss and containerCss options to allow styling through SimpleModal
* Added persist option to allow data to be "saved" across modal dialog calls
* Changed the handling of data. SimpleModal will now keep track of whether the
data came from the DOM and if it did, when the dialog is closed, it will re-insert it.
If persist is true, SimpleModal will re-insert the data in the state it was in when
closed, otherwise, it will re-insert a cloned value of the data.
* Added more CSS attributes to the overlay, container and iframe.
- There were a number of CSS attributes that were necessary for the modal dialog
to display correctly, so I moved them from the CSS, into SimpleModal.