Moved helper functions to separate file
Moved helper functions to separate file

CPIGroup/phpAmazonMWS,lapchenkovbyu/amazon-mws-laravel,HMAZonderland/phpAmazonMWS,creacoon/amazon-mws-laravel,Peardian/phpAmazonMWS,kibokosrl/phpAmazonMWS,VincentWon/mws