Fixes invalid unit test.
Fixes regression in right aligning rightAccessoryViews and improves the unit test.
Replaces old SC.SplitView with new version from experimental.  Includes several unit tests.
Reduces the number of dependencies for the Welcome and TestRunner app.  Fixes missing statechart dependency for TestRunner.
Gives SC.TreeController the jshint treatment and also adds the arrangedObjects observer on demand, which removes the need for a chained observer (== slightly less memory, faster).
Adds unit test showing that nulling out the content of an SC.TreeController will throw an exception.
Fixes exception when setting the content of an SC.TreeController (or any other object that nulls out arrangedObjects and mixes in SC.SelectionSupport).  Fixes previous commits failing unit test.
Fixes bug #990: SC.ListItemView Doesn’t Render Right Icons of the View’s rightIcon Property

The code for rendering a right icon was missing in the render method.
It has been added. Additionally the first part has been adapted to the
code for the (left) icon: In case of contentRightIconKey, it is only
rendered if a value exits for that key.
Minory cosmetic change

Added a space.
Bug #990: Adds unit test

Adds all unit tests for rightIcon of SC.ListItemView.