Improved doc wording.

modules/core/control.py

@@ -183,7 +183,7 @@ class EngineExecutor(Timer):
     """
     Base class for timed or threaded execution of Engine commands.
 
-    Primarly used for automation by the scheduler.
+    Primarily used for automations performed by the scheduler.
     """
     logger = logging.getLogger("AuraEngine")    
     timer_store = {}