test(watchGroup): fix incorrect expectations

watchGrp.detectChanges() returns the number of changes and as such can
never be null
feat(directives): remove the @Controller directive

Completely remove the deprecated Controller directive.

Major update to the demos to use setRootContext (where applicable) and
to move to Components for the beefier demos (bouncing balls and form).

A temporary work around was required in demos (animation and todo)
so that rootContext have Map interface. The work arounds will disappear
after the context is set to the component.

Library changes were pulled out of the first commit in #1269.