Composite Addon: Clean up code.

As the documentation says, it exposes one new methods.

The other three properties (runSuite, initFrame, iframe) were
needlessly added to the QUnit root object.

Also changed empty value of `test` to undefined.
Composite Addon: Fix inability to look into assertions

When clicking the test suites they "expand" however nothing
appears to happen as all the children of the test element
have forced display none.