clean up Lua frame handling a bit

There's no need to keep all this infrastructure to run every frame for a barely used situation.  This cleans it up a bit and does the position reset in the actual drawString function.

code/scripting/scripting.cpp

@@ -792,11 +792,6 @@ bool script_state::IsConditionOverride(int action, object *objp1, object *objp2,
 	return false;
 }
 
-void script_state::EndFrame()
-{
-	EndLuaFrame();
-}
-
 void script_state::Clear()
 {
 	// Free all lua value references