Make code slightly more rubyish

[orlando-labs]

Hi, @ankane, what do you think of the following ideas:

• [ ] renaming model-related methods :train and :eval to :train! and :eval! as the bang-methods looks semantically more correct in the context.
• [ ] adding alias :state_dict= to :load_state_dict

[ankane]

Thanks for the suggestions. This is a pretty subjective topic, but here are my initial thoughts:

• For train and eval, typically ! means there's a non-! method, which isn't the case here
• For load_state_dict, it feels more like a method to me than a setter (there's also a strict option that's not implemented yet)

[mib32]

I'd also say that's not so important

[ankane]

Cleaning up issues