Fix Mesh: Too many values to unpack

[ml14je]

In the README.md, it is suggested that to ensure that the vertices of each element are arranged in a counter-clockwise fashion, one simply uses the command points, cells = fix_mesh(points, cells). I had the error of two many values to unpack. Upon investigation, I could see that fix_mesh returns three outputs. To fix this in my own code, I simply changed it to

points, cells, jx = fix_mesh(points, cells)

Sorry, just thought others would find that helpful. (I have changed that in mine, and will submit a pull request once I am satisfied with other edits I have made.