|SOURCE|
[Common::Utility::Event]
* Member variables changed to protected for the Event class so inherited
  classes can access these members
|SOURCE|
[Common::Utility::EventRouter]
* Added a flag [ZED_DEBUG_EVENTMESSAGES] to control display of debug messages
  to the terminal
Merge branch 'utility_eventsystem' of https://github.com/OpenGameDevelopers/ZED into utility_eventsystem