BodySegmentation: flipped option doesn't work

[manuel-martos]

I've been experimenting a bit with combining the different models, and it seems like the 'flipped' option doesn't work for the bodySegmentation model. See the following screenshot as a reference:

[ziyuan-linn]

Hi @manuel-martos, thank you for reporting this!

When the flipped option is set to true, ml5.js sets flipHorizontal to true in the config object of the underlying Tensorflow.js models. I looked into the issue and discovered that the flipHorizontal option is documented but never implemented in the underlying tfjs body-segmentation model.

I am opening a PR to implement the flipping feature in ml5.js.