Sessions

Removed old code that is now in the Week class.
Revert "Sessions"

This reverts commit f049eebbf6a52e10add22f042ecedafe29e4d5c4.
Merge branch 'sessions' into settings
SessionsHandler

Commented some method signatures, and added a new method body to remove
all sessions stored on database.
--Merge (SessionHandler)--

Added some documentation to method signatures and a new method used to
delete all user sessions.