Merge pull request #47 from spininertia/master

fix doc
some doc
fix triangle
fix triangle
test postgres
add db test
change directory
dir bug
move legacy test
update travis
add large triangle test.
add youtube data
fix typo
fix reverse edge
fix reverse edge again;
add shortest path correctness test
Update README.md
add methof
add degree distribution
add task 1 test & update doc