v0.1.4

Fixes:

• params_dict recognises None when @ensure_list_arg is applied to a None argument
• make_order_request accepts str and int for conid, always casting it to int. 'coid' is now an optional parameter
• place_order now accepts multiple order requests in order to facilitate sending bracket orders
• added rest_07_bracket_orders.py
• fixed transaction_history request method