YITH Stripe Connect for WooCommerce Premium 2.31.0

* New: WooCommerce 3.7 support
* Tweak: add maxlenght to expiry date
* Tweak: now permit decimals to commission rate
* Update: internal plugin framework
* Update: Italian language
* Update: minify js files
* Dev: added new param to yith_wcsc_create_commission filter
* Dev: added new hook after connect with stripe action
* Dev: new filter yith_wcsc_args_create_charge
* Dev: added new filter yith_wcsc_commission_value
* Dev: add parameters to the filter yith_wcsc_commission_value

* Tweak: add no cache headers
* Tweak: improve how to get the CSV file
* Tweak: added ignore_user_abort
* Update: internal plugin framework
* Update: Updated .pot
* Fix: preventing notice when user_id not found in the receiver array
* Fix: warning when creating export CSV
* Fix: Fixed users could get all commissions in csv and pdf files
* Fix: Prevent error of insufficient funds of a card
* Fix: Removed undefined method add_block that generated fatal error with subscription item
* Fix: Fixed subscription renew orders payment issue
* Dev: Added wc-credit-card-form among yith-stripe-connect-js script dependencies, to be sure that it is always loaded at checkout
* Dev: Added new filters 'yith_wcsc_prepare_columns_list' and 'yith_wcsc_prepare_rows_list'

* Fix: js error preventing card submission