- IBAdapter: update market value with midpoint when security type is cash (e.g forex) because IB does not emit this tick for those products.

-IBClient: Basically, when IB error code 1101 happened, all previously subscription is lost, forcing one to restart the platform, but this code should fix that and automatically resubscribe any request.
Merge pull request #7 from dsimba/master

- IBAdapter: update market value with midpoint when security type is cas...