Some old work and some new (#3362)

* Some old work, some new

* c:style

* remove wrong version

redbot/cogs/mutes/errors.py

@@ -0,0 +1,21 @@
+class ControlFlowException(Exception):
+    """ 
+    The base exception for any exceptions used solely for control flow 
+    If this or any subclass of this ever propogates, something has gone wrong.
+    """
+
+    pass
+
+
+class NoChangeError(ControlFlowException):
+    pass
+
+
+class PermError(ControlFlowException):
+    """
+    An error to be raised when a permission issue is detected prior to an api call being made
+    """
+
+    def __init__(self, friendly_error=None, *args):
+        self.friendly_error = friendly_error
+        super().__init__(*args)