Support OpenPose tflite model (multi-pose)

[tucan9389]

Post-process Logic

• [x] 1. Get points from confidence map (make nodes) #38
• [x] 2. Make a bipartite graph with each part of points (make edges) #42
• [x] 3. Calculate line integral with PAF (compute costs of each edge) #42
• [x] 4. Connect each point and make human (solve assignment) #42
• [x] 5. Merge if a point is used duplicated in multiple human #42

Checklist

• [ ] Add parameter control UIs for PAF #47
• [ ] Limit the number of human on post-process #48
• [ ] Test other model

Reference

• https://arvrjourney.com/human-pose-estimation-using-openpose-with-tensorflow-part-2-e78ab9104fc8
• OpenPose: Realtime Multi-Person 2D Pose Estimation using Part Affinity Fields
• https://github.com/ildoonet/tf-pose-estimation