Device's Close method should implement io.Closer

[mdlayher]

Hello! I'm using hid in an upcoming project, and noticed that Device.Close has no return value. Since almost all Close functions in Go return an error, would it be acceptable to add an error return value to this method as well?

This would enable *hid.Device to easily implement io.Closer and io.ReadWriteCloser, and ensure that if any error return value is needed in the future, it can be easily adjusted.

Let me know what you think, and thank you for this package.

[karalabe]

Seems reasonable! :) Sorry, for not replying, I stopped looking at github notifications due to the crazy amounts I get and didn't see your comment. Will updated the repo with this change.

[karalabe]

Fixed via b77c67b.