add imu sub

svo/src/frame_handler_mono.cpp

@@ -156,7 +156,7 @@ FrameHandlerBase::UpdateResult FrameHandlerMono::processFrame()
     return RESULT_FAILURE;
   }
 
-  // pose optimization
+  // pose optimization subject to change for adding IMU
   SVO_START_TIMER("pose_optimizer");
   size_t sfba_n_edges_final;
   double sfba_thresh, sfba_error_init, sfba_error_final;