add new callbacks for new api api 9.69 (empty implementation)
attribute tradingClass moved to Contract struct (api 9.69)

This makes our xml files incompatible. Lets think how to deal
with this.
implement new callbacks (api 9.69)
Merge branch 'ib_proto_9.69' into next

* ib_proto_9.69:
  implement new callbacks (api 9.69)
  attribute tradingClass moved to Contract struct (api 9.69)
  add new callbacks for new api api 9.69 (empty implementation)
test: fix moved tradingClass attribute
twsxml: move tradingClass attribute for compatibility
test: adapt for tradingClass compatibility
Merge branch 'ib_proto_9.69' into next

* ib_proto_9.69:
  test: adapt for tradingClass compatibility
  twsxml: move tradingClass attribute for compatibility
  test: fix moved tradingClass attribute
Merge branch 'next'

* next:
  test: adapt for tradingClass compatibility
  twsxml: move tradingClass attribute for compatibility
  test: fix moved tradingClass attribute
  implement new callbacks (api 9.69)
  attribute tradingClass moved to Contract struct (api 9.69)
  add new callbacks for new api api 9.69 (empty implementation)