Improving journey docs and moving function to graph helper.
Improving journey docs and moving function to graph helper.

mapillary/OpenSfM,NicWayand/OpenSfM,onecue/OpenSfM,mapillary/OpenSfM,NicWayand/OpenSfM,onecue/OpenSfM,sunbingfengPI/OpenSFM_Test,oscarlorentzon/OpenSfM,edgarriba/OpenSfM,edgarriba/OpenSfM,NicWayand/OpenSfM,oscarlorentzon/OpenSfM,sunbingfengPI/OpenSFM_Test,onecue/OpenSfM,oscarlorentzon/OpenSfM,BrookRoberts/OpenSfM,oscarlorentzon/OpenSfM,mapillary/OpenSfM,BrookRoberts/OpenSfM,sunbingfengPI/OpenSFM_Test,edgarriba/OpenSfM,mapillary/OpenSfM,BrookRoberts/OpenSfM,NicWayand/OpenSfM,onecue/OpenSfM,BrookRoberts/OpenSfM,onecue/OpenSfM,oscarlorentzon/OpenSfM,sunbingfengPI/OpenSFM_Test,BrookRoberts/OpenSfM,sunbingfengPI/OpenSFM_Test,NicWayand/OpenSfM,edgarriba/OpenSfM,mapillary/OpenSfM,edgarriba/OpenSfM