Azure Storage sprint 40: support sas token used in operations and get/set service properties

Azure Storage sprint 40:

- Support sas token to be used in blob, file, table and queue operations by parameter --sas or --source-sas/--dest-sas (blob copy)

- Support get and set storage service logging properties

- Support get and set storage service metrics properties
This seems a little odd - are you trying to verify that value is a integer number, or an integer or a string that can be converted to an integer?

Initial testing seems to indicate this does work, but could you at least clarify the comment to explain exactly what this function does - is supporting strings expected here?