Fixed typographical error, changed auxilliary to auxiliary in README.

README.md

@@ -141,7 +141,7 @@ Double clicking the "Edit" button on the top left (the position will probably ch
 * Allows you to rename temperature probes -> Double click on any of the temperature probe headers
 * Allows you to create/delete PIDs
   * Edit a temperature probe, and add a GPIO pin for PID mode
-  * You can chose to add an extra GPIO for the auxilliary output that's manually controlled.
+  * You can chose to add an extra GPIO for the auxiliary output that's manually controlled.
 * Add custom named timers, click the "Add" button in the timer section.
 * Re-order the timers, click and drag to organize them
 * Add custom named Pump outputs, click the "Add" button in the pump section