functionObjects: Changed options 'outputControl' -> 'writeControl' and 'outputInterval' -> 'writeInterval'

for consistency with the time controls in controlDict and to avoid
unnecessary confusion.  All code and tutorials have been updated.

The old names 'outputControl' and 'outputInterval' are but supported for
backward compatibility but deprecated.

src/postProcessing/functionObjects/utilities/codedFunctionObject/codedFunctionObject.H

@@ -172,7 +172,7 @@ public:
         functionObject& redirectFunctionObject() const;
 
         //- Called at each ++ or += of the time-loop. forceWrite overrides the
-        //  outputControl behaviour.
+        //  writeControl behaviour.
         virtual bool execute(const bool forceWrite);
 
         //- Called when Time::run() determines that the time-loop exits.