Add a good amount of comments to most things that aren't getters/setters

...ithm/Multimodal/Heuristics/MultimodalModularHeuristic.cpp

...orithm/Multimodal/Heuristics/MultimodalModularHeuristic.h

src/algorithm/Multimodal/Heuristics/TransitAccess.h

src/algorithm/ShortestPath/Transit/TransitAlgorithmState.h

src/algorithm/ShortestPath/Transit/TransitShortestPath.h

...rithm/ShortestPath/Transit/TransitShortestPathContainer.h

src/algorithm/ShortestPath/Transit/TransitStateContainer.h

src/instance/Instance.h

src/instance/SAEVehicle.h

src/instance/graph/Graph.cpp

src/instance/graph/Graph.h

src/instance/graph/Line.h

src/instance/graph/LineStop.h

src/instance/requests/Request.h