Create notification system

[adamcik]

Firstly there are two types of notifications that need to be handled:

1. Short term notices, eg. "Adding course failed..."
2. Long term notices, eg. "Next semester available..."

Notifications can be targeted against:

• All users
• Users for a given semester
• Users for a given course (courses are linked to semesters)
• Given user
• Given user+semester

Notifications can be have the following types:

• None
• Success
• Notice
• Warning
• Error

Notifications can have a maximum age.

Notifications should be written in markdown.

Notifications should be stored in db and use caching.

Notifications should no rely on cookies or sessions.

Notifications should be available to code and admin.

Notications should solve/replace the following issues:

• Next semester loaded notifcations
• Short term user feedback, form errors etc.
• Common deadlines like cutoff date for signing up for new courses.

[adamcik]

Should take new django 1.2 notifications into account.

[adamcik]

Unsure how and if this should fit into the varnish caching scheme that the site is moving towards.