Standardized the naming of functions which control the writing of fields etc.

to have the prefix 'write' rather than 'output'

So outputTime() -> writeTime()

but 'outputTime()' is still supported for backward-compatibility.

Also removed the redundant secondary-writing functionality from Time
which has been superseded by the 'writeRegisteredObject' functionObject.

src/sampling/sampledSet/sampledSetsFunctionObject/sampledSetsDict

@@ -15,7 +15,7 @@ functions
 
         functionObjectLibs ("libsampling.so");
 
-        writeControl   outputTime;
+        writeControl   writeTime;
         setFormat       gnuplot;
         fields          (p U);
         interpolationScheme cellPoint;