minor cleanup
First pass of implementing Card on File integration
Move api functions into separate includes file
Move cardonfile callback functions into separate includes file
Convert URLs to constants
small cleanup and refactor of curl helper function
Flesh out submit_form_submit logic, and extract .api.inc create_profile function
Small cleanup of comments
Fill in Beanstream API functions to match version 1.1

* Add passcode setting to payment method for SPP integration
* Fix payment_profile_request() function to make general calls to the SPP API
* Add payment_profile_request_xml method to provide XML responseFormat for SPP API calls
* Adjust curl helper function to not parse response before returning
* Adjust commerce_beanstream_request() to parse QS format responses from curl before returning
Handle duplicate profile error, and refactor general handle_errors routine out of create_profile function
Refactor billing_address logic out of create_profile function
Card on File callbacks: complete logic for charge callback
Add helper function cardonfile_getcards
Implement Card on File update callback
Implement Card on File delete callback
Adjust submit_form_submit() routine to use fully-implement charge callback to process transactions
Adjust void_form_submit() routine to skip parsing now handled by commerce_beanstream_request()
Failed attempt at implementing Card on File create callback
General logic cleanup, removing unneeded functions etc
Add a bunch of missing doc comments to functions