Working on a few more updates and utils for the project. Working on getting a client to be able to send requests and responses and to be able to use an adapter so there is the potential to have a lot of fancy in the future
Updated because an invoice can only have one item attached, so it doesn't make sense to set a price twice
Updated so user need php >= 5.3.3 for some new upcoming changes
Updated the client so I can work on one request at a time
Added an example of how to create an invoice