WL-2820 Current courses are not old
WL-2820 add javadoc
WL-2820 Add javadoc to explain parameters
WL-2820 Add javadoc to explain return
WL-2820 Improve Javadoc.
Merge branch 'WL-2820'

Currently running courses are now considered new until they finish running, and then they become old. If we don't know when a course is running (no teaching dates) then we consider it old once the signup has finished.