Fix a few HCI types.
Fix the way return parameters are parsed.
Fix the way command complete and command status event flow control is supported.
The send_sync_command has been split now into two commands: send_sync_command that always checks the status and returns a class instance, and send_sync_command_raw that does not check the status and returns an HCI_Command_Complete_Event. This allows for better type checking than having a check_status argument, with a return type that could depend on that argument.