Thanks for your efforts in creating this plugin Daniel! I have not tested it deeply yet and also just on a demo account, but the basic functions from the TradeTest script work nicely (almost, see below*).
It's quite unfortunate that IG limits the non-trading requests to 30 per minute/account. With this limit I can only update 8 assets (e.g. with the Download script, saving all assets to AssetsNew.csv) before hitting the limit. I've asked for an increased limit, let's see if they comply with my request.

* When opening a position on a currency pair with Hedge=4, Zorro freezes. Other symbols work fine, see the logs below:

EUR/USD Mini, Hedge=4, Buy Long from TradeTest.c --> freeze
Code:
2017-06-21 14:56:57.113 [main] INFO  com.danlind.igz.brokerapi.BrokerBuy - >>> Creating long position epic=CS.D.EURUSD.MINI.IP, 
direction=BUY, 
expiry=-, 
size=1.0, 
orderType=MARKET, 
currency=USD, 
stop loss distance=0.5017
2017-06-21 15:17:58.759 [RxComputationThreadPool-3] WARN  c.danlind.igz.adapter.RestApiAdapter - Order with deal id DIAAAABCHXQZ5AX was rejected with reason code ATTACHED_ORDER_LEVEL_ERROR


Germany 30 Cash 1-EUR, Hedge=4, Buy Long from TradeTest.c --> works
Code:
2017-06-21 15:20:43.330 [main] INFO  com.danlind.igz.brokerapi.BrokerBuy - >>> Creating long position epic=IX.D.DAX.IFMM.IP, 
direction=BUY, 
expiry=-, 
size=1.0, 
orderType=MARKET, 
currency=EUR, 
stop loss distance=5748.0