Fix trivial spelling errors

- occured -> occurred
- reponse -> response
- seperated -> separated

All new code of the whole pull request, including one or several files
that are either new files or modified ones, are contributed under the
BSD-new license. I am contributing on behalf of my employer Amazon Web
Services, Inc.

dmlproc/dmlprocessor.cpp

@@ -839,7 +839,7 @@ void PackageHandler::run()
             }
             else
             {
-              // error occured. Receive all outstanding messages before erroring out.
+              // error occurred. Receive all outstanding messages before erroring out.
               batchProcessor->receiveOutstandingMsg();
               batchProcessor->sendlastBatch();  // needs to flush files
               batchProcessor->receiveAllMsg();