Add Intent Filter to link directly to notification settings on Android 5.0+ devices

Per Cyril Mottier's G+ post (https://plus.google.com/+CyrilMottier/posts/YY6tbJrJMra), Android 5.0 adds the ability to directly link to an application's notification settings when long pressing on the notification. Adding this functionality allows users to directly jump to Muzei's notification settings (part of the Advanced settings screen) from the notification.
Merge pull request #87 from ianhanniballake/notification_preferences_intent

Add Intent Filter to link directly to notification settings on Android 5...