set up interface specification
updated interface spec
Update Interfaces.md
Update Interfaces.md
Update title of interfaces.md
move original graph.jl
Merge branch 'bgl' of https://github.com/lindahua/Graphs.jl into bgl
upload concept graph
Add concept graph to interfaces.md
simple adjlist tested
refactored interfaces
add incidence_list.jl
generalized incidence list (tested)
further generalization (tested)
restructured graph types
revised graph_bench based on restructured graph types
BFS tested
graph requirement changes for bfs functions
add graph_visit and revise BFS (tested)
add traverse_graph_withlog (tested)