Implicitly call __toString method if action result is an object
If an action method returns an object, the ActionController should check if a __toString method exists and if so call it and append its result to the response content.
[+FEATURE] FLOW3 (MVC): If the result of an action method is an object providing a __toString() method, this method will be called by the ActionController and its result will be added to the response content. Resolves #5995
[+FEATURE] FLOW3 (MVC): The routes property @controller now allows the use of namespace separators for referring to classes in file / class structure below "Controllers". Resolves #5998
[~TASK] FLOW3 (Documentation): Fixed a few typos in the AOP documentation.