d3.js selection frame example.
improved version of my d3.js selection frame example (https://gist.github.com/lgersman/5310854) supporting draggable/selectable nodes
state diagram editor example based on (https://gist.github.com/lgersman/5311083)
improved state diagram editor based on https://gist.github.com/lgersman/5311202 featuring curvy connections with helper points