Print option values in the beginning of training.

[tannisroot]

trafficstars

Hi, here's an issue: recently, I started a training process with the new top-k option, and due to the change in the option name, i think it didn't get enabled as I used the new option name --top-k-training with an older version of stylegan2-pytorch which had it called --generate-top-k, resulting in a lot of wasted time :( I think it would be nice if the script could print values for various options before starting a new learning process, allowing users to easily spot whether they made a mistake when specifying a option.

[lucidrains]

@tannisroot sure! I can switch the CLI over to https://click.palletsprojects.com/en/7.x/ at some point, we can keep this open!