Base for settings dialog.
Add menu divider.
Process code in separate method.

This will allow for a cleaner implementation of #8.
Update Autoprefixer to current master branch.

This includes visual cascade.
Update Autoprefixer to version 1.1.
Add ellipsis to menu item.
Add visual cascade as an option in process method.
Working settings dialog.

Code is largely based on work by Martin Zaggora (@zaggino).

Resolves #8.