Adding support for ActivateAttribute via IControllerActivator

This mechanism replaces code in Inject that activated properties
by looking them up by names.


I was trying to avoid having to confuse the API consumer as to why there are two ways to get to the controller. 

> This interface is also somewhat limited
Wouldn't the consumer have to replace the ReflectedActionInvoker \ ControllerFactory to make this work? At which point, they could not use this interface at all.