Microsoft Research, Redmond, WA 98052, USA. jojic@microsoft.com|Microsoft Research, Redmond, WA 98052, USA. jojic@microsoft.com|Microsoft Research, Redmond, WA 98052, USA. jojic@microsoft.com|Microsoft Research, Redmond, WA 98052, USA. jojic@microsoft.com|Microsoft Research, Redmond, WA 98052, USA. jojic@microsoft.com