Remove some duplicate code by adding abstraction
Update Growl.framework to 2.0.1

As per https://code.google.com/p/growl/wiki/SystemRequirements this should not break compatibility with Sequel Pro and the API stays the same.
This change gives us Notification Center support for free, though.
Change how Growl status is displayed in prefs

The current status of Growl/Notification center will now be shown as a label beneath the "Enable notifications" checkbox.