QUnit Composite - First round of major cleanup

This first big sweep puts the addon into a much better state for further improvement via smaller and more incremental commits.

**Work done:**
 - Reduced surface area of API to minimum.
 - Corrected issue in 'qunit-composite.js' with use of inline style vs. CSS class that prevent results from ever being expanded.
 - Deleted 'index.html' as it was a pointless copy of the 'README.md'.
 - Renamed 'composite-demo-test.html' to 'composite.html' to match all of the other QUnit addons.
 - Added some special notes to the 'README.md'.