Bracket orders for combo legs

[simonskok]

Hi Ran,

thank you for writing this great module! It makes interaction with IB much easier.
As I am focused towards automating placing option spread combos, I have encountered the following issue: Combining your two examples from Readme file on placing an option combo and a bracket order, I get the following:

`import ezibpy
import time

ibConn = ezibpy.ezIBpy()
ibConn.connect(clientId=100, host="localhost", port=7496)

contract_to_buy = ibConn.createOptionContract("AAPL", expiry=20191101, strike=250, otype="CALL")
contract_to_sell = ibConn.createOptionContract("AAPL", expiry=20191101, strike=252.5, otype="CALL")

leg1 = ibConn.createComboLeg(contract_to_buy , "SELL", ratio=1)
leg2 = ibConn.createComboLeg(contract_to_sell , "BUY", ratio=1)
contract = ibConn.createComboContract("AAPL", [leg1, leg2])

order = ibConn.createBracketOrder(contract,
quantity = 1,
entry = 0.02,
target = 0.05,
stop = 0.01)
`

Missing or invalid NonGuaranteed value. REL+MKT, LMT+MKT, and REL+LMT order of two legs can only be set as non-guaranteed.

I have configured my API setting in IB TWS to allow Non-guaranteed execution, but the error remains. Looking through your source code, I also havent been able to locate the variable corresponding to this setting.

Any idea how to solve this?