Add PRE_PROCESS_ORDER and POST_PROCESS_ORDER
Added billing invoice
make fluent the methods in payment profile billing properties
Added methods to payment profile interface
Added 'paid' boolean property
move BillingInvoice work into BillingRequest
fix doc blocks
Removed order and added pricing set and partner
remove unneeded Invoice classes
refactor to use Pimple based PricingContext
Added isAllFree method to check order content
update Agreement and Request to include PaymentProfile
CS
added getters, setters for payment gateway
updates for items in billing agreement and request
updates to generate billing requests
Moved the check for require billing setup in the model
start code for processing BillingAgreement, post BillingRequest creation
extending pimple on payment profile
fixed when credit card was empty
added getters and setters for pricing set to billing request
added gs for amountDue in BR