4.3 - Easier to read, no unlimited

Unlimited notifications was going to be way too hard to fully
integrate, so the user can just set the value to a very high number.
4.3 - LOTS of changes

- Full notification revamp - number of notifications in sidebar should
accurately reflect NumOfNot value: the right notifications are deleted
at the right times
- There should be no "Where is system events.app?" dialog any more
- Actually adds the app to login items
- Should update app path
- Better "Remove on quit"