Rewrite of edit_distance with edge costs. fix #111

[etiennedeg]

Fix #111

I changed the default costs, as otherwise, the default algorithm as absolutely no meaning. I kept in the file the MinkowskiCost and BoundedMinkowskiCost to avoid breakage because they are exported, but we should deprecate these methods, they are useless IMO.

I adapted the code to fix the support of directed graphs and self loops.

I kept the same type of implementation as before with a BFS , but I don't think that's a great idea, this allocates tremendously, even for rather small graphs. It should be good to rewrite this as a backtracking algorithm with some more efficient pruning, or using constraint programming or linear programming. IMO, we should at some point move it to the future GraphOptim, I don't think we have many exponential complexity functions in the code base, and this function merit a slightly more involved implementation.

[codecov]

Codecov Report

Merging #137 (8a755ac) into master (11f54ad) will decrease coverage by 0.10%.
The diff coverage is 95.55%.

@@            Coverage Diff             @@
##           master     #137      +/-   ##
==========================================
- Coverage   97.26%   97.17%   -0.10%     
==========================================
  Files         114      114              
  Lines        6579     6649      +70     
==========================================
+ Hits         6399     6461      +62     
- Misses        180      188       +8     

[gdalle]

The tests fail because they now include doctests, it shouldn't be too hard to adapt?