WooCommerce Lightspeed POS Integration 2.16.6

New - Adds support for persistent cache (Memcached or Redis)

* Fix - Fixes a category import bug where categories of with the same name are assigned to the incorrect products
* Fix - Fixes a bug where Webstore properties (long, short, LxWxH) were not being synced from WC->LS correctly
* Fix - MySQL bugfix for versions > 8.0. The "system" column in the wclsi_attribute_sets table is a reserved keyword. Renames the column to "sys".
* Tweak - Ensure attributes are updated every 30s
* Tweak - Adds a register_taxonomy() call for new product attributes, this ensures attribute taxonomies are created instantly
* New - Fixes up PHPUnit tests. Automated tests are now run on every new commit, PR, and before every release.

* New - **MAJOR CHANGE** ALL syncing is now done with the action scheduler queue
* New - Lightspeed Import page can now search for SKU values, Category values, as well as regular and sale prices via the search input
* New - New "Remove Uncategorized" setting which will attempt at removing the "Uncategorized" category when importing products from Lightspeed
* New - New "Category Sync Settings" tab that is specific to categories
* Fix - Bulk editing through the Woo page should now queue changes up instead of causing 429 errors
* Fix - Removes the "WCLSI_UPDATE_CANCELLED_ORDER" option which can cause sync failures
* Fix - JS fix around the case where there are 0 categories to import from Lightspeed
* Tweak - Removed "Order Sync" settings
* Tweak - Removed "Manual "
* Tweak - Disable the "Search Lightspeed" button if the plugin has not being initiated yet
* Tweak - Sets a default '0.0' value for WCLSI_DB_VERSION_OPTION so DB migrations run better
* Tweak - On Category import, try and match Lightspeed categories to ones that already exist in Woo
* Tweak - When pushing a product to Lightspeed from Woo (creating a new product), refresh the page
* Tweak - When pushing a product to Lightspeed from Woo, use the lowest level category id that is linked to Lightspeed for propery category matching