Update OAuth events example to use new classes

[GKFX]

The changes to the Propel example are not tested but are based on the changes I have made to my own Symfony project.

The Symfony example is deliberately sparse, since the Propel example already exists, and is mostly intended to resolve confusion regarding what the new name of the event is.

[GKFX]

That's fine with me, I've applied the changes

[deguif]

Thanks @GKFX