Remove instantiating Device as BW::Device

I'd like to suggest that we remove the convenience of instantiating Device as BW::Device if it is not defined.

The reason why is that this causes a name spacing problem that forces you to handle your load paths, which can cause a lot of headaches. Since BubbleWrap has already been shorten to BW, typing BW::Device isn't too far from typing Device.

It will also prevent other gems that rely on BW to explicitly call BW::Device instead of assuming that Device is BW::Device.

What do you think? I'd love to hear your thoughts on it.

Thank you!