move graph info to a stats class
Enabling topology-driven BFS
Bug removed  from topo
topology-driven version bfs

unfortunately, the code is a little buggy
round bit mask version
round-queue version
add  a log util & recode stats
change pinned memory to normal one
enable texture memory
add up some scripts
remove the texture memory
decouple the contraction and expansion
add a class to calculate the metrics

: )
combine order and unordered version
a big commit after silence
Merge branch 'Venus'