Created "clone"

Now events allow multiple sessions and to add a new session of the
given event item.  Needed for Generic Events, but I don’t see a reason
*not* to have it for the other cases.
Merge branch 'master' of https://github.com/bethlakshmi/GBE2

Conflicts:
	expo/scheduler/views.py

Merging cloning update into other updates on main line.
Fixing (I hope) conflict in views.py