Release v1.3.1

Changelog:

• Added alot more placeholders and finished custom fields placeholders
• Added storeCategories and storeProducts endpoints by @overkidding
• Fixed a few custom field types included a html code in the value
• Fixed products listing showing incorrect currency
• Fixed incorrect page identifier when using more dropdown
• Fixed that shipping details are no longer needed by @overkidding
• Fixed return screen for PayPal Business gateway returned alot of debug information