Nodes have reversed positions to edges.

I found out Vivagraph few weeks ago. It`s really interesting. But I met a problem when I render .png images with webgl, nodes and edges are reversed.

When I select node and move it works wrong on Y axis.

Start by reproducing the reported .png rendering with WebGL and the node-selection drag interaction. Compare node and edge orientation and Y-axis movement against the screenshot and expected graph positions. Done means rendered nodes and edges have the correct orientation and selected nodes move correctly on the Y axis.

Written by the indexing model from the issue text.