Doco links to dead-ish downloads page on Github

[tripleee]

http://cork.firelet.net/ says

Fully working examples are provided with the sources

where the link is to the existent but unhelpful page https://github.com/FedericoCeratto/bottle-cork/downloads -- it would perhaps be better to link to e.g. the parent page https://github.com/FedericoCeratto/bottle-cork or perhaps directly to https://github.com/FedericoCeratto/bottle-cork/tree/master/examples