Adapting to Exhibit 3.0 - RequireJS

This is just an arbitrary point in the work, I'll need to leave off for a bit.  The general progression is to move all the Freemix scripts to use Require - and they're pretty close, given the pattern already in place - and bring them in via freemix-main.

The Exhibit / Timeline / SimileAjax versions committed are all the latest in their respective repositories as of this comment, Exhibit from the requirejs branch.