Added fail safe to protect interface discovery
Added fail safe to protect interface discovery

As described in https://github.com/TheImagingSource/tiscamera/issues/7
The interface discovery crashes as the currently iterated interface
does not exhibit all expected information.
The fail safe checks if the interface has a valid sub struct and is
described as running.

TheImagingSource/tiscamera,TheImagingSource/tiscamera,TheImagingSource/tiscamera,TheImagingSource/tiscamera