Complete BTER Implementation

The adaption of open orders definitely needs a second pair of eyes.  They don't provide an order type so I had to get a bit creative.

Also, there seems to be an issue with the order id returned when placing an order.  I get back a successful response but the order id doesn't correspond the actual open order.  On top of that, if you create an order with insufficient funds it still returns success with an order id but an actual order is never created.  I've contacted their support and this is the response I got:

Dear Sir,
Sorry we can not return a" false " for now.The order you placed enters to the waitlist and the system can not judge it immediately to give you a false message. I am afraid you have to pay attention to your balance yourself and check if your order is created. 
Hope we can improve it in the future.And thanks again for your support