[be2bill] reorganize be2bill classes. remove src folder.
[offline] reorganize offline component classes. remove src folder.
[omnipay-bridge] reorganize omnipay bridge component classes. remove src folder.
[payex] reorganize payex bridge component classes. remove src folder.
[paypal ec] reorganize paypal ec component classes. remove src folder.
[paypal pro checkout] reorganize paypal pro component classes. remove src folder.
[paypal iipn] reorganize paypal ipn component classes. remove src folder.
composer add replace section.
[paypal rest] reorganize paypal rest component classes. remove src folder.
add paypal rest to phpunit.xml