Add an intro to the documentation
Add an intro to the documentation

Ignore-this: 868e280fe97227472ae47102c4383c88

darcs-hash:20121022171945-a85e5-4f410113631c873d9cd5e28939fb1fe1697f8c1a

chuajiesheng/oclosure-old,chuajiesheng/oclosure-old,chuajiesheng/oclosure-old