Value is not Implemented for Option<T>

[AmoleR]

#1585 added impl Value for Option<T> so we weren't writing cumbersome code, but this code is not implemented in the master branch (upcoming release).

I don't think there should be any reason to not include this in the master, and it would help greatly.

If you would like, I could tackle this.

[safinaskar]

See valuable branch. It makes impl Value for Option not needed. But I disagree with how they solved the problem, my arguments are here: #2777

[davidbarsky]

We'll be removing the Value trait in 0.2 and replacing it with valuable, so while it is kind of you to offer to implement this, it's not necessary :)