- Added a RETI instruction for returning 15-bit signed immediate values.

- Changed Actor's Damage property into an actual function. All access to the damage property
  must now be done through GetMissileDamage. actor->GetMissileDamage(0, 1) is equivalent
  to the former actor->Damage, for the case where actor->Damage was not an expression. (I
  suppose I will probably need to make a thunk for DECORATE expressions that want to read it.)
- Cleaned up some decorate expression evaluation functions that are no longer used.

SVN r3919 (scripting)

src/info.cpp

@@ -302,6 +302,9 @@ size_t PClassActor::PropagateMark()
 			GC::Mark(OwnedStates[i].ActionFunc);
 		}
 	}
+	// Mark damage function
+	GC::Mark(((AActor *)Defaults)->Damage);
+
 //	marked += ActorInfo->NumOwnedStates * sizeof(FState);
 	return Super::PropagateMark();
 }