influence maximization 3, 1,2 to debug, @jianfei
influence maximization 3 revised
rewrite inf-max using  map_reduce_vertices, waiting for before_iteration api
Fix inf-max 2 and 3
Retab
Merge pull request #46 from kimiyoung/inf-max

Fix inf-max 2 and 3
Merge pull request #50 from neozhangthe1/map_reduce_context

added context in mapreduce interface
merge inf-max code
add return value for map reduce