allowing sort in read-only-slave mode and only deny sort Command with st...

Allowing sort command in read-only-slave

1] removing "w" attribute from sort Command
2] and prohibit writing with store option in sortCommand when it is read only slave.

but. I might think this is not a good approach. because it is weak that someone add new option to new option.

so. how about add some other command only to store it's result to list.(ex. sortAndStore)