Draw graph in graph theory and export it to TikZ.
Demo page: https://nedchu.github.io/graphjs/Graph%20Theory%20JS_HTML5.html
Based on source in https://dl.dropboxusercontent.com/u/4189520/GraphJS/graphjs.html
Alt+Click: Add vertex
Alt+Shift+Click: Add edge
X, Y axis of vertex are multiple of 10
Export graph to TikZ and compile it in LaTeX
Export graph to Json