WooCommerce Lightspeed POS Integration 2.16.6

* Better error handling
* Fixes a bug that did not allow products to load fully if an error occured

* Adds refresh token logic for Aug 1st Lightspeed deadline
* Fixes bug where products with a single tag do not sync over correctly

* Fixes a bug where WooCommerce products were not set to "Out of Stock" if synced inventory was 0
* Fixes a bug where out of stock variation products were not being synced over to Lightspeed
* Minor fixes to error notifications when syncing a product to Lightspeed