Issue #176: made actor deregistration more robust

apps/openmw/mwmechanics/actors.cpp

@@ -71,7 +71,10 @@ namespace MWMechanics
 
     void Actors::removeActor (const MWWorld::Ptr& ptr)
     {
-        mActors.erase (ptr);
+        std::set<MWWorld::Ptr>::iterator iter = mActors.find (ptr);
+
+        if (iter!=mActors.end())
+            mActors.erase (iter);
     }
 
     void Actors::dropActors (const MWWorld::Ptr::CellStore *cellStore)

apps/openmw/mwmechanics/actors.hpp

@@ -32,6 +32,8 @@ namespace MWMechanics
 
             void removeActor (const MWWorld::Ptr& ptr);
             ///< Deregister an actor for stats management
+            ///
+            /// \note Ignored, if \a ptr is not a registered actor.
 
             void dropActors (const MWWorld::Ptr::CellStore *cellStore);
             ///< Deregister all actors in the given cell.