Revert "[Revert later!] Change value to monitor in callbacks: val_loss -> loss"
Revert "[Revert later!] Change value to monitor in callbacks: val_loss -> loss"

This reverts commit 1dcd304e90f1143b738afeda4e9b7a3e758329ea.

danieljl/keras-image-captioning,danieljl/keras-image-captioning