API client class v1.1.93

- added the migrate_device() method to migrate one or more devices from one controller to another
- added the cancel_migrate_device() method to cancel the migration for one or more devices
- added the upgrade_all_devices() method to upgrade all devices of a selected type to the latest firmware version
- changed the force_provision() method to allow for multiple MAC addresses to be passed as a parameter
- minor changes to a number of doc-blocks
- general changes for improved consistency and readability