Code that exposes invokers to listeners in the pre-init functions should be commented

Several of the components use a strategy of pre-definining an invoker in the pre-init function so that they can be used in the listeners block. The code for this looks strange though, since it relies on the framework to re-write the function underneath. This should be properly commented in all situations.

see the chat in the irc channel around 08:39
http://wiki.fluidproject.org/display/fluid/fluid-work+IRC+Logs-2012-05-15