Adds unit tests for SC.CollectionView integration with design modes.
Fixes SC.CollectionView integration with design modes. Don't set the designMode as an attribute directly, because updateDesignMode will be called on the child view properly when it is added. If designMode is set beforehand, then updateDesignMode will fast path out thinking there is no change (rather than apply the modeAdjust adjustments).

Fixes previous failing unit tests.