fixed S&T thread and potential timer too close errors

README.md

@@ -40,6 +40,8 @@ Follow these steps to install the Shake&Tune module in your printer:
      # show_macros_in_webui: True
      #    Mainsail and Fluidd doesn't create buttons for "system" macros that are not in the
      #    printer.cfg file. If you want to see the macros in the webui, set this to True.
+     # timeout: 300
+     #    The maximum time in seconds to let Shake&Tune process the CSV files and generate the graphs.
      ```
 
 ## Usage