Create a new section exclusive for Reminders

Right now, Reminders are mixed with replies to Topics and Tasks.  I think that Reminders are more important because those were set by the users reminding themselves of something that they had to do, as opposed to some other user writing them about something.

Also:

- The system could set a default period of 7, 14 or 30 days to "purge" old notifications and reminders, letting users change the settings of those to longer periods (2 months, 3 months, 6 months, 1 year).

- Both Notifications and Reminders should be SORTABLE by date from Oldest to Newest and Newest to Oldest.