improve information on "Creating a New Module" page

It would be helpful if executeRead was explained further since it isn't being manually invoked. It would also be nice if the documentation wrote filenames for which files it was referring to. I originally was looking in views/ for the template.

(Originally posted to Trac as ticket #1091 on 2009-04-19T13:01:29+00:00 by @bnovc)

[Xylakant]

The execute methods are explained in http://www.agavi.org/documentation/tutorial/a-word-about-actions.html. I'll add a reference to that page in the later chapter.

(Originally posted to Trac on 2009-04-28T09:43:27+00:00)