Return empty list if no blobs were found.
Return empty list if no blobs were found.

* Fixes #81

openmv/openmv,iabdalkader/openmv,iabdalkader/openmv,kwagyeman/openmv,iabdalkader/openmv,openmv/openmv,kwagyeman/openmv,iabdalkader/openmv,openmv/openmv,openmv/openmv,kwagyeman/openmv,kwagyeman/openmv