Tweaks to Observer mixin.
Initial pass at adding control: config merging between view controller superclasses and subclasses; initial control merging tests.
Allow for complex merged control: scenario where one class uses a "non-simple" configuration for a control target, but the parent or child uses a simple configuration for the same control target.
Finish initial control: merge logic; add more tests; add view controller behavior functionality along with associated tests.
Tweaks and refactoring around control: merging; regenerate docs.