fix SSSP (currently need to stick additional 'new_dist' into Vertex rather than VertexProgram
fix SSSP (currently need to stick additional 'new_dist' into Vertex rather than VertexProgram

alexfrolov/grappa,buaasun/grappa,alexfrolov/grappa,alexfrolov/grappa,buaasun/grappa,buaasun/grappa,alexfrolov/grappa,uwsampa/grappa,buaasun/grappa,buaasun/grappa,uwsampa/grappa,alexfrolov/grappa,alexfrolov/grappa,uwsampa/grappa,uwsampa/grappa,alexfrolov/grappa,buaasun/grappa,uwsampa/grappa,uwsampa/grappa,buaasun/grappa,uwsampa/grappa