Finer Grained Notification Controls

[fennifith]

Add options to discern between different types of notifications - maybe somehow keeping track of the ids (and titles as well, so the user can actually tell what they mean) and adding the ability to block certain numbers.

On second thought, keeping track of the notifications might not be such a great idea. However, I could at least allow the user to block persistent notifications (one option on the icon settings to block ALL persistent notifications, and one on the app settings to block them from individual apps).

• fix Redesign App-Specific Settings #146
• icon settings ui
• implementation in the notification icon

[fennifith]

On second thought, notifications should not appear in the 'apps' tab. Now that #115 is finished, it'd be better and more obvious to simply put these settings in the notification icon. It would also make sense from a maintenance standpoint, since all of the notification-related spaghetti will then be in the Notification* classes.