Move links above stats on crates.io

[alexcrichton]

Moved over from rust-lang/cargo#924:

@chriseppstein says: "Stats are cool, but I wanted to go to the code repo and it took me forever to find it."

[chriseppstein]

Thanks!

[eddyb]

Detecting popular code hosting sites and using their logo (or maybe just grabbing the favicon?) would be helpful for noticing a link to the repo even faster.

[pwoolcoc]

+1

[kud1ing]

I think the top-right area above the authors would be a good place for the homepage and the repository links.

[killercup]

Anyone working on this? I might send a PR for this later today. See #73.

[alexcrichton]

Fixed in #73 (landed in #77)