Calendar overlay portlet revamp

We could make the overlay an object with it's own edit view and a link to it.

So we could:

1. Allow users giving custom names to calendar overlays.

At the moment we should at least supply sensible defaults depending on the uset
that is overlaying ...
The teacher would get "Sixth Grade Maths"
A learner would get "Maths"
not the 3 lines of junk one gets now ...

2. The TT checkbox could be moved to the said overlay Edit/View form so it could
have a proper explanation near it.
3. Color select box would be a nice addition too ...
4. Maybe settings of whether said overlay should be included in PDF
calendar/atom feed generated

Just brainstorming ...