|SOURCE|
[Common::Utility::Event]
* Private members changed to protected so derived classes can acess them
[Common::Utility::EventRouter]
* Global EventRouter variable was not working before (it was definded as
  static, where it should have been extern) as when an EventRouter
  instance was instanciated, the pointer was not being modified
|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