WooCommerce Connector implemented

[kidunot89]

trafficstars

Partially resolves #1093

Summary checklist

• [x] deleted_post callback tested and passing.
• [x] transition_post_status callback tested and passing.
• [x] woocommerce_attribute_added callback tested and passing.
• [x] woocommerce_attribute_deleted callback tested and passing.
• [x] woocommerce_attribute_updated callback tested and passing.
• [x] woocommerce_order_status_changed callback tested and passing.
• [x] woocommerce_tax_rate_added callback tested and passing.
• [x] woocommerce_tax_rate_deleted callback tested and passing.
• [x] woocommerce_tax_rate_updated callback tested and passing.
• [x] ~updated_option callbacks tested and passing.~ Stubbed.