fix: revise np.amin, np.amax and add np.argmin

the bool to tensor has a bug, if in init the training is False, the program not start.

fix: Fix the problem where the  model.save_weights() can't save multi-layer weight

fix: inconsistent shape error while training embedding layer

I added `ToArray()` so that there is no "The collection has changed" error after `_delete_tracking`.

refactor: Standardize TensorFlowNET.Keras/Losses/*

fix: type converting errors when loading imdb dataset