Implement transport maps

[andymina]

Avidan et al. describe transport maps as a tool to find the optimal path of seam alteration in an image. Right now, seams are removed/inserted in alternating order with preference to remove vertical seams first.

When implementing, it might be worth adding a new function or flag parameter to the existing seam carving function in src/CarvableImage.cpp to use the optimal seam removal/insertion order found through transport times. This is purely for semantics since the results between alternating seam alteration and transport maps are fairly similar.