Add algorithm for finding the shortest route

[kdemmich]

Add algorithms for finding the shortest route:

• using route_through_array from skimage
• using genetic algorithm with BOAT_TYPE="speedy_isobased"

[kdemmich]

partly solved by 98e9e78

[SahebSandhuSingh]

Hi @kdemmich is this still open can I still contribute to this??

[PavanendraBaahubali]

Hi @kdemmich, can I work on this issue? I’ve already signed the CLA and sent it via email.

[saiprasad578]

"Hi @kdemmich, I have recently submitted PR #103 for thread-safety and have my CLA on file. I would like to help complete this issue by implementing the skimage.graph.route_through_array portion. Is this still open for contribution?"