Moved EventSystem over to pointer-based system.
Finished moving system over to pointer-based system.
Returned TRUE in registerListener.

Note: Might want to check for proper insertion if we're really concerned
about listener integrity, or, the registerListener function could return a
pointer to the listener attached. NULL would represent an improper
addition, a pointer gives the calling class a reference to its inline
created object.
Whoops. Made sure the parameter default is not redeclared in imp.