* added handling of truncated and difficult attributes for pascal voc
loader/dumper
added descriptions of supported annotation formats
* added YOLO example
* made match_frame as Annotations method
changed 'image/source_id' field TF feature from int64 to string
(according to TF OD API dataset utlis)
* updated README
improved match_frame function
* added unit tests for dump/load
* Disable fix_segments_intersections for now
When the bounding boxes had intersections and were exported with the COCO JSON format they were often cut off. I commented out the line with the function fix_segments_intersections and replaced it with lines of that function. This helped with the bounding boxes and keeps the masks as they are created with CVAT. It is probably inconvenient for the user to get something fixed in the export without an active agreement of the user. Secondly letting a function automatically fix segments could result in a bad fix.
* Use fix_segments_intersections only with z-order
The fix_segments_intersections will only be used when the z-order flag is set. This is useful for bounding boxes or masks which don't need to be fixed. This fix was created according to Andrey Zhavoronkov's (@azhavoro) advice.
zhiltsov-max
Andrey Zhavoronkov
Johannes222