feat(directive): support as instance syntax

Support controller: 'MyController as my' syntax for directives which publishes
the controller instance to the directive scope.

Support controllerAs syntax to define an alias to the controller within the
directive scope.
feat(directive): support as instance syntax

Support controller: 'MyController as my' syntax for directives which publishes
the controller instance to the directive scope.

Support controllerAs syntax to define an alias to the controller within the
directive scope.