TAPS-146: Provide some way to get the component that fired an event

[Taha Hafeez]

Hi

I was looking at https://issues.apache.org/jira/browse/TAP5-146 and had an
idea. What if you could push a service (say EventContext, or some other name
as it is already in use) onto the environment which contains the component
triggering the action. This can easily be done
in ComponentEventRequestHandlerImpl and AjaxComponentEventRequestHandler. So
we would be able to do something like

@Environmental
private EventContext context;

void onMyEvent()
{
   context.getSource() ...
}

regards
Taha