Lacosmicx

I have finished the optimized LA Cosmic implementation. It uses Cython for the main part of the algorithm and uses C for the individual routines. Everything is multithreaded using OpenMP (the Cython standard). For a 4K x 2K image, this implementation is ~35 times faster than cosmics.py written by Malte Tewes (which is already significantly faster than the original IRAF version). 

Given the complexity of this code, should this be included in imageutils or should it be its own package? 

Any other comments are welcome.
That is a good question. There is a section about public domain from the GNU projects at https://www.gnu.org/licenses/license-list.html. Perhaps a comment from Nicolas Devillard would be enough.  This is all based on the paper at http://ndevilla.free.fr/median/median.pdf. I wasn't able to find a journal or proceedings reference for the work.