Support using the call api while training

[joeyballentine]

Implements my idea mentioned in #292. While i'm not sure its a great idea to have people use the call api while training, i suppose it's probably a good idea to at least make it work if they do choose to do so.

[RunDevelopment]

Sorry. I see now that my comment was super unclear/misleading, but I didn't mean to suggest that the call API should support training, I was just lamenting about the fact that this can't be the case.

I think that the call API should not support training. It doesn't make sense. Some arches output more than just an image, and some arches need more than just an input image to train. There are even arches that are trained in multiple stages (e.g. AdaCode). So having the call API "work" for training would just be foot gun, since it will either fail or silently do the wrong thing for some arches.

So I agree that people should just use the arches directly for training.

[joeyballentine]

Ok cool