Add func to replays

docs/idareplayobserver.rst

@@ -9,7 +9,7 @@ IDAReplayObserver
 
    .. method:: IDAReplayObserver.on_game_start(self)
 
-      This method is called when a replay has stared, when you inherit it you have to
+      This method is called when a replay has started, when you inherit it you have to
       call the parent's on_game_start method in order to make it work (see
       :ref:`replays`).
 
@@ -25,6 +25,14 @@ IDAReplayObserver
       call the parent's on_game_start method in order to make it work (see
       :ref:`replays`).
 
+   .. method:: IDAReplayObserver.on_unit_created(self)
+
+      This method is called when the an unit is created, that includes when an unit leaves a refinery.
+
+   .. method:: IDAReplayObserver.on_unit_destroyed(self)
+
+      This unit is called when a unit is destroyed.
+
    Methods:
 
    .. method:: IDAReplayObserver.get_all_units(self) -> List[library.ReplayUnit]