Work on event manager

Leslie,
I've got an event manager coded, but untested and it's api will probably still change somewhat. It's in eventmanager.js

I've been working on testing it, learning how to create the simplest "widget" I could, which once it works can be expanded on. That's very rough code in eventmanagerTests.html.

In my repo I also removed the .DS_Store files which are local Mac directory management files.